Medicare Advantage Enrollment Tracker

Medicare Advantage Enrollment by County

In September 2026, individual Medicare Advantage plans had 30,149,164 members in 3,115 counties. Half of them live in 159 counties. The largest is Los Angeles, CA, with 817,043.

Data as ofSeptember 2026CMS, individual plans

County counts are individual plans only. Group plans are left out.
Why this matters
County members, 12-month change and leading carrier: individual Medicare Advantage plans (employer group excluded), September 2026. A county with no individual plan reads "not reported", not 0.
MA share of Medicare comes from a 2024 file. It is older than the counts.
Why this matters
Share of Medicare in Medicare Advantage: CMS Geographic Variation file, 2024. It is older than the member counts and is never divided into them.
A county with no individual plan reads as not reported, not zero.
Why this matters
Counties with no individual Medicare Advantage plan row are left out of the ranked table.

By Senior Deal Club Standards Desk. Editorial policy. Methodology. Senior Deal Club is not affiliated with Medicare or any government agency. This page is educational. It counts members. It does not rate plans.

Counts here are individual plans only. Employer and union group plans are not in them, so they are smaller than the state and carrier counts on other tracker pages. Do not compare across pages.

Counties ranked

Individual Medicare Advantage members, September 2026. County names are plain text for now.

Individual plans · September 2026

Individual Medicare Advantage plans. Employer and union group plans are left out. A county with no individual plan is not reported.

Showing the first 500 of 3,115 counties. Pick a state to see the rest.

Individual Medicare Advantage by county, September 2026. 12-month change is the change in individual plan members. MA share of Medicare is from the 2024 CMS file.
County	State	Members	12-month change	MA share of Medicare, 2024 file	Leading carrier (share of individual members)
1. Los Angeles	CA	817,043	up 3.2 percent	63%	Kaiser Permanente (30%)
2. Miami-Dade	FL	391,941	up 1.5 percent	81%	UnitedHealthcare (30%)
3. Maricopa	AZ	371,288	up 3.0 percent	55%	UnitedHealthcare (34%)
4. Harris	TX	350,369	up 3.7 percent	67%	UnitedHealthcare (31%)
5. Cook	IL	327,148	up 2.4 percent	49%	Humana (41%)
6. Orange	CA	296,250	up 3.2 percent	61%	SCAN (29%)
7. San Diego	CA	284,862	up 2.5 percent	60%	Kaiser Permanente (30%)
8. Riverside	CA	248,115	up 2.5 percent	69%	Kaiser Permanente (26%)
9. Broward	FL	238,442	up 2.1 percent	71%	Humana (56%)
10. Queens	NY	232,928	up 2.8 percent	65%	Healthfirst, Inc. (40%)
11. Clark	NV	229,400	up 3.5 percent	62%	Humana (36%)
12. Kings	NY	213,699	up 2.3 percent	61%	Healthfirst, Inc. (40%)
13. San Bernardino	CA	203,033	up 2.9 percent	74%	Kaiser Permanente (28%)
14. Bexar	TX	177,151	up 3.6 percent	62%	UnitedHealthcare (44%)
15. Dallas	TX	176,359	up 3.1 percent	60%	UnitedHealthcare (51%)
16. Allegheny	PA	169,421	up 1.1 percent	75%	UPMC Health System (37%)
17. King	WA	167,129	up 1.6 percent	60%	UnitedHealthcare (47%)
18. Palm Beach	FL	165,192	up 1.9 percent	51%	Humana (58%)
19. Hillsborough	FL	159,668	up 2.9 percent	66%	Humana (44%)
20. Wayne	MI	159,353	up 2.3 percent	68%	Humana (24%)
21. Tarrant	TX	157,971	up 3.4 percent	62%	UnitedHealthcare (59%)
22. Bronx	NY	151,965	up 2.6 percent	76%	Healthfirst, Inc. (56%)
23. Philadelphia	PA	151,102	up 1.7 percent	65%	Independence/BCBS (27%)
24. Pinellas	FL	146,204	up 1.3 percent	64%	Humana (39%)
25. Cuyahoga	OH	138,067	up 1.4 percent	63%	UnitedHealthcare (27%)
26. Orange	FL	133,801	up 3.4 percent	66%	Humana (45%)
27. Pima	AZ	133,082	up 3.0 percent	61%	UnitedHealthcare (56%)
28. Santa Clara	CA	129,894	up 3.9 percent	58%	Kaiser Permanente (51%)
29. New York	NY	128,617	up 0.3 percent	52%	Healthfirst, Inc. (48%)
30. Erie	NY	127,376	up 2.2 percent	77%	Lifetime Healthcare, Inc. (28%)
31. Hennepin	MN	123,575	down 2.9 percent	67%	BCBS Minnesota (46%)
32. Sacramento	CA	122,357	up 5.2 percent	67%	Kaiser Permanente (54%)
33. Polk	FL	117,193	up 4.0 percent	71%	Humana (47%)
34. St. Louis	MO	114,648	up 2.6 percent	61%	UnitedHealthcare (40%)
35. Monroe	NY	111,471	up 1.1 percent	83%	Lifetime Healthcare, Inc. (65%)
36. El Paso	TX	107,040	up 3.9 percent	78%	UnitedHealthcare (36%)
37. Alameda	CA	104,559	up 4.8 percent	59%	Kaiser Permanente (73%)
38. Oakland	MI	100,929	up 4.9 percent	59%	BCBS Michigan (25%)
39. Franklin	OH	99,510	up 1.3 percent	62%	Humana (24%)
40. Duval	FL	99,466	up 3.9 percent	56%	UnitedHealthcare (39%)
41. Volusia	FL	97,954	up 3.0 percent	63%	Humana (48%)
42. Lee	FL	97,666	up 4.5 percent	52%	UnitedHealthcare (41%)
43. Pasco	FL	96,992	up 3.1 percent	70%	Humana (46%)
44. Hartford	CT	96,428	up 0.9 percent	–	UnitedHealthcare (30%)
45. Milwaukee	WI	95,862	up 1.3 percent	71%	UnitedHealthcare (56%)
46. Middlesex	MA	95,384	up 1.3 percent	38%	Point32Health, Inc. (40%)
47. Salt Lake	UT	94,237	up 3.5 percent	63%	UnitedHealthcare (44%)
48. Hidalgo	TX	91,353	up 4.8 percent	80%	HCSC/BCBS (30%)
49. Honolulu	HI	90,199	up 0.8 percent	64%	UnitedHealthcare (40%)
50. New Haven	CT	86,040	up 2.1 percent	–	Aetna/CVS (35%)
51. Brevard	FL	85,792	up 3.9 percent	53%	Health First Shared Services, Inc. (33%)
52. Marion	IN	85,239	up 3.1 percent	62%	Humana (33%)
53. Nassau	NY	83,496	up 4.4 percent	35%	Aetna/CVS (30%)
54. Suffolk	NY	82,482	up 5.2 percent	31%	Aetna/CVS (44%)
55. Providence	RI	82,019	up 1.3 percent	71%	BCBS Rhode Island (47%)
56. Macomb	MI	81,212	up 4.4 percent	62%	Humana (23%)
57. Snohomish	WA	80,398	up 2.0 percent	66%	UnitedHealthcare (57%)
58. Mecklenburg	NC	80,289	up 4.8 percent	59%	UnitedHealthcare (39%)
59. Multnomah	OR	80,166	up 0.5 percent	73%	UnitedHealthcare (27%)
60. Pierce	WA	79,896	up 2.8 percent	55%	UnitedHealthcare (59%)
61. Contra Costa	CA	78,389	up 0.9 percent	60%	Kaiser Permanente (79%)
62. Marion	FL	77,987	up 4.6 percent	62%	UnitedHealthcare (35%)
63. Hamilton	OH	76,965	up 1.2 percent	62%	Humana (28%)
64. Shelby	TN	76,280	up 3.4 percent	51%	Humana (29%)
65. Jefferson	AL	75,255	up 1.7 percent	73%	BCBS Alabama (23%)
66. Kent	MI	74,307	up 3.9 percent	77%	Corewell Health (69%)
67. Worcester	MA	73,606	up 2.8 percent	48%	BCBS Massachusetts (20%)
68. Fulton	GA	73,605	up 2.9 percent	61%	Humana (34%)
69. Wake	NC	70,076	up 6.0 percent	56%	UnitedHealthcare (30%)
70. Bernalillo	NM	69,095	up 1.5 percent	66%	Presbyterian Healthcare Services (35%)
71. Summit	OH	68,800	up 1.8 percent	68%	UnitedHealthcare (23%)
72. Jackson	MO	68,253	up 2.9 percent	61%	Humana (40%)
73. Guilford	NC	68,192	up 3.8 percent	74%	UnitedHealthcare (34%)
74. Gwinnett	GA	65,797	up 6.3 percent	64%	Humana (34%)
75. Lake	FL	65,788	up 4.8 percent	58%	Humana (34%)
76. Montgomery	OH	65,189	up 1.8 percent	65%	Elevance/Anthem/BCBS (31%)
77. Fresno	CA	64,716	up 2.8 percent	52%	Alignment Health (30%)
78. Clark	WA	64,662	up 3.3 percent	74%	Humana (30%)
79. Jefferson	LA	63,966	up 1.4 percent	77%	Humana (55%)
80. Westmoreland	PA	63,697	up 1.9 percent	76%	UPMC Health System (32%)
81. Spokane	WA	63,473	up 2.4 percent	60%	UnitedHealthcare (63%)
82. Jefferson	CO	63,349	up 1.7 percent	69%	UnitedHealthcare (50%)
83. Fairfield	CT	62,125	down 2.2 percent	–	UnitedHealthcare (38%)
84. Fort Bend	TX	61,877	up 6.0 percent	61%	UnitedHealthcare (37%)
85. Tulsa	OK	61,424	up 3.7 percent	55%	UnitedHealthcare (36%)
86. Washington	OR	61,112	up 2.1 percent	72%	UnitedHealthcare (33%)
87. Jefferson	KY	60,633	up 2.8 percent	54%	Humana (54%)
88. Oklahoma	OK	59,883	up 3.5 percent	48%	UnitedHealthcare (42%)
89. San Francisco	CA	59,002	up 5.1 percent	56%	Kaiser Permanente (41%)
90. DeKalb	GA	58,934	up 3.3 percent	67%	Humana (36%)
91. Essex	MA	58,887	up 2.2 percent	38%	UnitedHealthcare (28%)
92. Westchester	NY	58,746	up 3.9 percent	42%	Aetna/CVS (26%)
93. Montgomery	PA	58,594	up 2.2 percent	40%	Independence/BCBS (46%)
94. Sarasota	FL	58,585	up 3.1 percent	44%	UnitedHealthcare (38%)
95. San Joaquin	CA	58,417	up 3.8 percent	59%	Kaiser Permanente (45%)
96. Collin	TX	57,990	up 6.2 percent	47%	UnitedHealthcare (57%)
97. Lane	OR	57,812	up 0.7 percent	68%	UnitedHealthcare (53%)
98. Lancaster	PA	57,664	up 1.8 percent	54%	Highmark/BCBS (32%)
99. Clackamas	OR	57,217	up 1.6 percent	73%	UnitedHealthcare (32%)
100. El Paso	CO	57,202	up 3.1 percent	54%	UnitedHealthcare (48%)
101. Ada	ID	55,949	down 2.0 percent	63%	UnitedHealthcare (39%)
102. Ventura	CA	55,891	up 0.7 percent	46%	Kaiser Permanente (41%)
103. Kern	CA	55,617	up 2.3 percent	51%	Kaiser Permanente (28%)
104. Stark	OH	55,480	up 2.4 percent	72%	UnitedHealthcare (23%)
105. Greenville	SC	54,938	up 2.8 percent	51%	Humana (39%)
106. Mobile	AL	54,692	up 2.7 percent	74%	UnitedHealthcare (27%)
107. Waukesha	WI	53,846	up 3.2 percent	63%	UnitedHealthcare (57%)
108. Pinal	AZ	53,635	up 6.8 percent	60%	UnitedHealthcare (34%)
109. Osceola	FL	53,489	up 5.4 percent	76%	Humana (42%)
110. Onondaga	NY	53,351	up 2.7 percent	66%	Lifetime Healthcare, Inc. (33%)
111. Bergen	NJ	53,295	up 4.5 percent	40%	UnitedHealthcare (39%)
112. Ramsey	MN	52,844	down 2.1 percent	69%	BCBS Minnesota (41%)
113. Arapahoe	CO	52,745	up 2.2 percent	64%	UnitedHealthcare (44%)
114. Essex	NJ	52,292	up 3.8 percent	55%	UnitedHealthcare (44%)
115. DuPage	IL	52,181	up 2.4 percent	43%	Humana (53%)
116. Manatee	FL	52,175	up 2.6 percent	51%	Humana (42%)
117. St. Lucie	FL	51,870	up 4.0 percent	59%	Humana (51%)
118. Horry	SC	51,775	up 6.6 percent	46%	Humana (40%)
119. Bucks	PA	51,648	up 1.6 percent	45%	Independence/BCBS (52%)
120. Cameron	TX	51,008	up 4.5 percent	77%	HCSC/BCBS (35%)
121. Knox	TN	50,932	up 1.8 percent	57%	Humana (56%)
122. York	PA	50,564	up 2.6 percent	55%	Aetna/CVS (40%)
123. Forsyth	NC	50,413	up 3.5 percent	71%	UnitedHealthcare (34%)
124. Montgomery	TX	50,404	up 5.0 percent	56%	UnitedHealthcare (35%)
125. Stanislaus	CA	49,957	up 3.0 percent	61%	Alignment Health (37%)
126. Denver	CO	49,934	up 1.5 percent	67%	UnitedHealthcare (36%)
127. San Mateo	CA	49,805	up 4.1 percent	58%	Kaiser Permanente (59%)
128. Davidson	TN	49,352	up 1.6 percent	62%	HCSC/BCBS (34%)
129. Denton	TX	49,083	up 4.8 percent	50%	UnitedHealthcare (57%)
130. Travis	TX	48,286	up 2.4 percent	52%	Humana (42%)
131. Sonoma	CA	48,277	up 0.3 percent	58%	Kaiser Permanente (80%)
132. Middlesex	NJ	47,770	up 5.0 percent	45%	UnitedHealthcare (40%)
133. Seminole	FL	47,425	up 3.0 percent	58%	Humana (45%)
134. Bristol	MA	47,333	up 2.9 percent	41%	UnitedHealthcare (24%)
135. Cobb	GA	47,072	up 2.6 percent	54%	Humana (38%)
136. Hampden	MA	46,905	up 0.4 percent	49%	CareSource (29%)
137. Dakota	MN	46,789	up 0.6 percent	67%	BCBS Minnesota (50%)
138. Washoe	NV	46,510	up 4.0 percent	51%	Renown Health (41%)
139. Suffolk	MA	46,267	down 0.4 percent	47%	UnitedHealthcare (29%)
140. San Juan	PR	46,157	down 3.1 percent	–	MHH Healthcare, L.P. (55%)
141. Orleans	LA	46,128	up 1.8 percent	75%	Humana (45%)
142. Fairfax	VA	45,489	up 3.8 percent	38%	Kaiser Permanente (28%)
143. St. Charles	MO	44,718	up 4.0 percent	64%	UnitedHealthcare (43%)
144. Hudson	NJ	44,352	up 3.8 percent	60%	Clover Health Holdings, Inc. (38%)
145. East Baton Rouge	LA	44,091	up 2.9 percent	69%	Humana (53%)
146. Allen	IN	44,075	up 3.4 percent	68%	UnitedHealthcare (41%)
147. Norfolk	MA	43,930	up 2.7 percent	36%	Point32Health, Inc. (30%)
148. Lucas	OH	43,838	up 2.0 percent	62%	Medical Mutual Of Ohio (27%)
149. Sedgwick	KS	43,751	up 2.9 percent	47%	UnitedHealthcare (36%)
150. Hamilton	TN	43,563	up 3.1 percent	58%	BCBS Tennessee (50%)
151. Johnson	KS	43,145	up 2.4 percent	45%	UnitedHealthcare (36%)
152. Sumter	FL	42,690	up 4.6 percent	57%	UnitedHealthcare (56%)
153. Douglas	NE	42,603	up 2.4 percent	49%	UnitedHealthcare (46%)
154. Anoka	MN	41,298	up 0.7 percent	72%	BCBS Minnesota (41%)
155. Marion	OR	41,106	up 1.2 percent	70%	UnitedHealthcare (53%)
156. Adams	CO	41,070	up 3.4 percent	71%	UnitedHealthcare (44%)
157. Cumberland	ME	40,967	up 1.4 percent	65%	Martin's Point Health Care, Inc. (45%)
158. Hernando	FL	40,643	up 2.9 percent	70%	Elevance/Anthem/BCBS (35%)
159. Delaware	PA	40,593	up 1.8 percent	43%	Independence/BCBS (42%)
160. Utah	UT	40,401	up 5.9 percent	61%	UnitedHealthcare (38%)
161. Spartanburg	SC	40,201	up 4.1 percent	56%	Humana (49%)
162. Ocean	NJ	39,878	up 3.2 percent	41%	Horizon/BCBS (33%)
163. Erie	PA	39,085	up 2.1 percent	67%	Aetna/CVS (44%)
164. Ottawa	MI	38,928	up 4.3 percent	80%	Corewell Health (75%)
165. Nueces	TX	38,907	up 2.4 percent	69%	UnitedHealthcare (59%)
166. Placer	CA	38,827	up 4.4 percent	61%	Kaiser Permanente (59%)
167. Berks	PA	38,629	up 2.8 percent	49%	Highmark/BCBS (25%)
168. Richmond	NY	38,571	up 3.2 percent	51%	Aetna/CVS (30%)
169. Genesee	MI	37,930	up 5.7 percent	70%	Humana (22%)
170. Greene	MO	37,904	up 2.5 percent	64%	Humana (25%)
171. Polk	IA	37,850	up 3.4 percent	47%	UnitedHealthcare (36%)
172. Brown	WI	37,775	up 3.2 percent	74%	Network Health, Inc. (41%)
173. Passaic	NJ	37,680	up 4.2 percent	53%	Clover Health Holdings, Inc. (36%)
174. Mohave	AZ	37,196	up 4.0 percent	54%	Humana (65%)
175. Collier	FL	37,194	up 3.4 percent	39%	UnitedHealthcare (40%)
176. Plymouth	MA	36,999	up 2.3 percent	34%	Point32Health, Inc. (24%)
177. Will	IL	36,517	up 3.2 percent	46%	Humana (50%)
178. Escambia	FL	36,069	up 3.8 percent	51%	Humana (44%)
179. Charlotte	FL	36,017	up 4.9 percent	53%	Humana (40%)
180. Butler	OH	35,980	up 2.7 percent	60%	UnitedHealthcare (24%)
181. Prince George's	MD	35,847	down 1.3 percent	37%	Kaiser Permanente (47%)
182. Citrus	FL	35,644	up 5.0 percent	58%	Humana (37%)
183. Montgomery	MD	35,297	down 1.5 percent	27%	Kaiser Permanente (52%)
184. Lake	IL	34,909	up 4.3 percent	37%	Humana (55%)
185. Camden	NJ	34,677	up 3.4 percent	49%	Clover Health Holdings, Inc. (21%)
186. Union	NJ	34,370	up 3.7 percent	52%	UnitedHealthcare (41%)
187. Lorain	OH	34,164	up 4.5 percent	60%	UnitedHealthcare (20%)
188. Lake	IN	34,157	up 4.8 percent	49%	Elevance/Anthem/BCBS (28%)
189. Lehigh	PA	34,009	up 2.7 percent	50%	Highmark/BCBS (33%)
190. Williamson	TX	33,948	up 4.3 percent	51%	Humana (39%)
191. Yavapai	AZ	33,918	up 2.2 percent	44%	Humana (39%)
192. Pulaski	AR	33,638	up 3.1 percent	48%	UnitedHealthcare (35%)
193. St. Tammany	LA	33,375	up 2.6 percent	66%	Humana (47%)
194. Mahoning	OH	32,724	up 0.6 percent	68%	UnitedHealthcare (27%)
195. New Castle	DE	32,700	up 2.9 percent	36%	UnitedHealthcare (32%)
196. Richland	SC	32,615	up 5.1 percent	45%	Humana (47%)
197. Niagara	NY	32,447	up 3.6 percent	77%	UnitedHealthcare (24%)
198. Dane	WI	32,445	up 0.8 percent	43%	Medica (30%)
199. Washington	PA	32,059	up 2.6 percent	73%	Highmark/BCBS (33%)
200. Solano	CA	31,557	up 0.5 percent	62%	Kaiser Permanente (87%)
201. Baltimore	MD	31,479	up 2.3 percent	28%	Kaiser Permanente (24%)
202. Baldwin	AL	31,330	up 4.3 percent	60%	UnitedHealthcare (29%)
203. Winnebago	IL	31,289	up 2.8 percent	61%	Aetna/CVS (49%)
204. Baltimore City	MD	31,224	down 0.5 percent	40%	Kaiser Permanente (20%)
205. Washington	MN	31,114	up 0.9 percent	68%	BCBS Minnesota (48%)
206. Luzerne	PA	30,882	up 3.1 percent	47%	Risant Health, Inc. (51%)
207. Cumberland	NC	30,532	up 6.2 percent	56%	Humana (38%)
208. Bayamon	PR	30,140	down 4.7 percent	–	MHH Healthcare, L.P. (53%)
209. Canyon	ID	29,901	up 0.4 percent	68%	UnitedHealthcare (35%)
210. Larimer	CO	29,864	up 3.3 percent	51%	UnitedHealthcare (41%)
211. Sullivan	TN	29,809	up 1.4 percent	71%	BCBS Tennessee (41%)
212. Madison	AL	29,777	up 6.6 percent	50%	Humana (26%)
213. Bell	TX	29,680	up 3.7 percent	55%	Baylor Scott & White Health (40%)
214. Beaver	PA	29,471	up 1.4 percent	77%	Highmark/BCBS (36%)
215. Outagamie	WI	29,433	up 3.9 percent	77%	Network Health, Inc. (57%)
216. Butler	PA	29,410	up 3.0 percent	74%	Highmark/BCBS (33%)
217. St. Louis City	MO	29,399	up 0.7 percent	71%	UnitedHealthcare (39%)
218. Jefferson	MO	29,383	up 2.9 percent	70%	UnitedHealthcare (35%)
219. District of Columbia	DC	29,350	up 0.7 percent	–	UnitedHealthcare (68%)
220. St. Louis	MN	29,286	down 3.9 percent	73%	Medica (47%)
221. Chester	PA	29,224	up 1.1 percent	36%	Independence/BCBS (37%)
222. York	ME	28,925	up 2.3 percent	57%	Martin's Point Health Care, Inc. (29%)
223. Virginia Beach City	VA	28,895	up 3.6 percent	36%	Humana (52%)
224. Jackson	OR	28,870	up 2.1 percent	51%	Regence/BCBS (27%)
225. Oneida	NY	28,577	up 2.9 percent	57%	Lifetime Healthcare, Inc. (38%)
226. Northampton	PA	28,572	up 4.2 percent	46%	Highmark/BCBS (24%)
227. Dauphin	PA	28,548	up 3.1 percent	65%	Highmark/BCBS (31%)
228. Trumbull	OH	28,493	up 1.8 percent	65%	UnitedHealthcare (23%)
229. Lake	OH	28,452	up 3.0 percent	58%	Elevance/Anthem/BCBS (24%)
230. Galveston	TX	28,363	up 4.4 percent	61%	UnitedHealthcare (33%)
231. Monmouth	NJ	28,141	up 3.9 percent	34%	UnitedHealthcare (29%)
232. St. Joseph	IN	28,031	up 3.0 percent	57%	UnitedHealthcare (47%)
233. Charleston	SC	27,913	up 1.9 percent	39%	Humana (31%)
234. Brazoria	TX	27,888	up 6.0 percent	63%	UnitedHealthcare (37%)
235. Kane	IL	27,744	up 1.7 percent	44%	Humana (46%)
236. Douglas	CO	27,685	up 4.3 percent	57%	UnitedHealthcare (48%)
237. Weld	CO	27,486	up 4.0 percent	59%	Humana (38%)
238. Gaston	NC	27,208	up 3.5 percent	65%	UnitedHealthcare (29%)
239. Thurston	WA	27,139	up 1.9 percent	56%	UnitedHealthcare (50%)
240. Ponce	PR	27,077	up 1.3 percent	–	MHH Healthcare, L.P. (44%)
241. Hillsborough	NH	26,775	down 2.7 percent	41%	UnitedHealthcare (41%)
242. Davis	UT	26,717	up 5.1 percent	58%	UnitedHealthcare (46%)
243. Davidson	NC	26,682	up 3.9 percent	75%	UnitedHealthcare (32%)
244. St. Johns	FL	26,402	up 4.4 percent	41%	Humana (36%)
245. Muskegon	MI	26,336	up 4.4 percent	76%	Corewell Health (43%)
246. Albany	NY	26,177	up 2.7 percent	62%	Lifetime Healthcare, Inc. (44%)
247. Chatham	GA	26,105	up 2.7 percent	58%	Humana (40%)
248. Winnebago	WI	26,095	up 2.4 percent	74%	Network Health, Inc. (53%)
249. Anderson	SC	26,057	up 3.3 percent	55%	Humana (45%)
250. Lexington	SC	26,014	up 4.2 percent	42%	Humana (41%)
251. Saratoga	NY	25,966	up 4.1 percent	62%	Lifetime Healthcare, Inc. (48%)
252. Burlington	NJ	25,828	up 5.0 percent	46%	UnitedHealthcare (26%)
253. Cumberland	PA	25,801	up 4.8 percent	55%	Highmark/BCBS (31%)
254. New London	CT	25,773	up 1.2 percent	–	Aetna/CVS (33%)
255. Kent	RI	25,743	up 1.6 percent	67%	BCBS Rhode Island (55%)
256. Buncombe	NC	25,602	up 3.0 percent	50%	Humana (34%)
257. Madison	IL	25,599	up 2.5 percent	57%	UnitedHealthcare (47%)
258. Clayton	GA	25,360	up 5.3 percent	76%	Humana (37%)
259. St. Clair	IL	25,184	up 1.7 percent	59%	UnitedHealthcare (46%)
260. Chesterfield	VA	25,089	up 3.6 percent	41%	Humana (46%)
261. Kalamazoo	MI	24,770	up 2.3 percent	70%	Corewell Health (49%)
262. Rutherford	TN	24,709	up 3.6 percent	56%	BCBS Tennessee (32%)
263. Racine	WI	24,691	up 3.4 percent	65%	UnitedHealthcare (52%)
264. Henrico	VA	24,617	up 4.0 percent	44%	Humana (43%)
265. Dona Ana	NM	24,556	up 3.9 percent	56%	UnitedHealthcare (70%)
266. Benton	AR	24,544	up 3.0 percent	54%	Humana (47%)
267. Hinds	MS	24,442	up 3.5 percent	56%	Humana (41%)
268. Boulder	CO	24,322	up 1.9 percent	53%	UnitedHealthcare (45%)
269. York	SC	24,139	up 4.0 percent	48%	Humana (33%)
270. Tulare	CA	24,036	up 6.1 percent	38%	Humana (36%)
271. Clermont	OH	23,821	up 2.8 percent	62%	Humana (29%)
272. Cambria	PA	23,815	up 1.4 percent	80%	UPMC Health System (55%)
273. Hamilton	IN	23,628	up 4.9 percent	47%	UnitedHealthcare (40%)
274. Washington	UT	23,491	up 5.5 percent	51%	UnitedHealthcare (35%)
275. Caddo	LA	23,457	up 1.1 percent	54%	Humana (46%)
276. Weber	UT	23,316	up 4.0 percent	59%	UnitedHealthcare (45%)
277. Webb	TX	23,214	up 7.8 percent	67%	UnitedHealthcare (49%)
278. Alamance	NC	23,177	up 3.6 percent	74%	UnitedHealthcare (33%)
279. Yuma	AZ	23,095	up 5.6 percent	52%	Centene/Wellcare (36%)
280. Indian River	FL	23,038	up 3.3 percent	44%	UnitedHealthcare (40%)
281. Flagler	FL	22,967	up 4.9 percent	56%	Humana (51%)
282. Carolina	PR	22,952	down 2.5 percent	–	MHH Healthcare, L.P. (54%)
283. Orange	NY	22,883	up 5.5 percent	39%	UnitedHealthcare (27%)
284. Linn	IA	22,750	up 2.0 percent	50%	Aetna/CVS (42%)
285. Leon	FL	22,739	up 2.0 percent	67%	Florida Blue/BCBS (49%)
286. Montgomery	AL	22,674	up 2.1 percent	68%	UnitedHealthcare (41%)
287. Randolph	NC	22,595	up 3.3 percent	77%	UnitedHealthcare (29%)
288. Broome	NY	22,350	up 1.8 percent	67%	Lifetime Healthcare, Inc. (31%)
289. McLennan	TX	22,342	up 3.4 percent	58%	UnitedHealthcare (53%)
290. Hawaii	HI	22,329	up 2.3 percent	55%	UnitedHealthcare (35%)
291. Jefferson	TX	22,253	up 1.9 percent	63%	Humana (31%)
292. Brunswick	NC	22,191	up 9.9 percent	43%	Humana (46%)
293. Harrison	MS	22,063	up 5.2 percent	50%	Humana (61%)
294. Durham	NC	21,974	up 4.3 percent	56%	UnitedHealthcare (34%)
295. Iredell	NC	21,815	up 5.5 percent	61%	UnitedHealthcare (36%)
296. Sussex	DE	21,739	up 3.4 percent	31%	UnitedHealthcare (51%)
297. Lubbock	TX	21,629	up 3.8 percent	55%	Humana (35%)
298. Henry	GA	21,617	up 5.7 percent	67%	Humana (44%)
299. Caguas	PR	21,617	down 4.2 percent	–	MHH Healthcare, L.P. (64%)
300. Richmond	GA	21,547	up 3.0 percent	65%	Humana (42%)
301. Whatcom	WA	21,541	up 1.8 percent	53%	UnitedHealthcare (40%)
302. Cabarrus	NC	21,486	up 5.4 percent	65%	UnitedHealthcare (32%)
303. Catawba	NC	21,419	up 5.5 percent	62%	UnitedHealthcare (29%)
304. Litchfield	CT	21,369	up 4.1 percent	–	Aetna/CVS (42%)
305. Morris	NJ	21,320	up 4.7 percent	37%	UnitedHealthcare (47%)
306. Pueblo	CO	21,265	up 3.1 percent	65%	UnitedHealthcare (55%)
307. Kitsap	WA	20,893	up 4.1 percent	43%	UnitedHealthcare (35%)
308. Clay	FL	20,819	up 5.1 percent	44%	Humana (40%)
309. Marin	CA	20,804	down 0.7 percent	50%	Kaiser Permanente (87%)
310. Lackawanna	PA	20,788	up 1.9 percent	47%	Risant Health, Inc. (49%)
311. Penobscot	ME	20,766	up 0.7 percent	61%	UnitedHealthcare (29%)
312. Warren	OH	20,715	up 2.8 percent	57%	Elevance/Anthem/BCBS (26%)
313. Smith	TX	20,664	up 5.4 percent	51%	Humana (33%)
314. Alachua	FL	20,625	up 2.2 percent	45%	Humana (58%)
315. Sumner	TN	20,619	up 1.8 percent	59%	HCSC/BCBS (42%)
316. Atlantic	NJ	20,612	up 5.4 percent	46%	Clover Health Holdings, Inc. (37%)
317. Shelby	AL	20,529	up 4.6 percent	66%	BCBS Alabama (42%)
318. Fayette	KY	20,402	up 3.1 percent	59%	Humana (47%)
319. Dutchess	NY	20,389	up 3.7 percent	44%	UnitedHealthcare (32%)
320. Rockingham	NH	20,317	down 1.5 percent	35%	UnitedHealthcare (40%)
321. Highlands	FL	20,206	up 3.6 percent	59%	Humana (45%)
322. Chautauqua	NY	20,137	up 2.8 percent	67%	Aetna/CVS (26%)
323. Washington	TN	20,077	up 2.9 percent	64%	UnitedHealthcare (48%)
324. Fayette	PA	20,063	up 2.0 percent	70%	UPMC Health System (36%)
325. Saginaw	MI	20,040	up 5.2 percent	70%	Humana (28%)
326. Prince William	VA	20,006	up 7.4 percent	40%	Humana (33%)
327. Marathon	WI	19,921	up 1.2 percent	68%	Marshfield Clinic Health System, Inc. (60%)
328. Washtenaw	MI	19,916	up 4.6 percent	64%	BCBS Michigan (29%)
329. Washington	WI	19,823	up 4.5 percent	66%	UnitedHealthcare (53%)
330. Berkeley	SC	19,812	up 4.4 percent	45%	Humana (37%)
331. Johnson	TX	19,700	up 3.7 percent	64%	UnitedHealthcare (65%)
332. Rowan	NC	19,645	up 3.6 percent	69%	UnitedHealthcare (37%)
333. Portage	OH	19,557	up 4.3 percent	67%	UnitedHealthcare (21%)
334. Cherokee	GA	19,545	up 3.6 percent	52%	Humana (37%)
335. Yakima	WA	19,498	up 1.1 percent	47%	UnitedHealthcare (57%)
336. Clay	MO	19,461	up 4.6 percent	52%	Humana (63%)
337. Lancaster	NE	19,455	up 3.0 percent	37%	UnitedHealthcare (42%)
338. Johnston	NC	19,399	up 6.5 percent	59%	UnitedHealthcare (42%)
339. Union	NC	19,388	up 6.1 percent	55%	UnitedHealthcare (31%)
340. Elkhart	IN	19,358	up 2.9 percent	55%	UnitedHealthcare (38%)
341. Medina	OH	19,179	up 3.0 percent	59%	Elevance/Anthem/BCBS (19%)
342. Kanawha	WV	19,148	up 3.0 percent	63%	Humana (40%)
343. Mercer	PA	19,067	up 2.2 percent	70%	Aetna/CVS (38%)
344. Muscogee	GA	19,059	up 4.4 percent	58%	Humana (40%)
345. Middlesex	CT	19,019	up 1.3 percent	–	Aetna/CVS (30%)
346. Licking	OH	18,877	up 3.5 percent	60%	Trinity Health Corporation (25%)
347. Santa Rosa	FL	18,758	up 5.8 percent	47%	Humana (42%)
348. Blair	PA	18,738	up 1.8 percent	67%	UPMC Health System (50%)
349. Martin	FL	18,555	up 2.7 percent	42%	Humana (55%)
350. Arecibo	PR	18,436	up 1.2 percent	–	MHH Healthcare, L.P. (53%)
351. New Hanover	NC	18,401	up 6.7 percent	45%	Humana (60%)
352. Norfolk City	VA	18,385	up 3.9 percent	53%	Humana (42%)
353. Linn	OR	18,328	down 0.1 percent	66%	Centene/Wellcare (28%)
354. Deschutes	OR	18,196	down 2.8 percent	45%	PacificSource (100%)
355. Cleveland	OK	18,162	up 3.9 percent	43%	Humana (42%)
356. Mercer	NJ	18,104	up 4.8 percent	51%	UnitedHealthcare (32%)
357. Kootenai	ID	18,080	down 6.8 percent	48%	UnitedHealthcare (39%)
358. Ontario	NY	18,080	up 1.8 percent	78%	Lifetime Healthcare, Inc. (74%)
359. Sandoval	NM	18,067	up 3.6 percent	62%	Presbyterian Healthcare Services (36%)
360. Kennebec	ME	18,033	up 1.7 percent	67%	Martin's Point Health Care, Inc. (31%)
361. Richmond City	VA	17,953	up 1.1 percent	58%	Humana (36%)
362. Bibb	GA	17,948	up 3.2 percent	64%	UnitedHealthcare (43%)
363. Aiken	SC	17,948	up 3.4 percent	45%	Humana (52%)
364. Cowlitz	WA	17,870	up 2.9 percent	70%	UnitedHealthcare (40%)
365. Ingham	MI	17,719	up 4.9 percent	71%	Humana (38%)
366. Stearns	MN	17,644	down 0.7 percent	60%	BCBS Minnesota (77%)
367. Blount	TN	17,532	up 2.3 percent	59%	Humana (51%)
368. Lafayette	LA	17,529	up 5.4 percent	42%	Humana (41%)
369. Franklin	MO	17,480	up 4.0 percent	76%	UnitedHealthcare (54%)
370. McHenry	IL	17,419	up 5.4 percent	39%	Humana (55%)
371. Douglas	OR	17,394	up 1.2 percent	53%	ATRIO Health Plans (71%)
372. Rockingham	NC	17,393	up 3.0 percent	78%	UnitedHealthcare (40%)
373. Bay	FL	17,367	up 5.7 percent	43%	Humana (51%)
374. Schenectady	NY	17,190	up 2.8 percent	68%	Lifetime Healthcare, Inc. (37%)
375. Washington	RI	17,176	up 1.2 percent	57%	BCBS Rhode Island (54%)
376. Robeson	NC	17,173	up 3.4 percent	73%	UnitedHealthcare (41%)
377. St. Clair	MI	17,124	up 6.4 percent	64%	Humana (32%)
378. Barnstable	MA	16,937	down 1.2 percent	26%	BCBS Massachusetts (49%)
379. Ellis	TX	16,915	up 6.6 percent	57%	UnitedHealthcare (64%)
380. Gloucester	NJ	16,876	up 5.3 percent	46%	Humana (20%)
381. Chesapeake City	VA	16,867	up 4.1 percent	41%	Humana (43%)
382. Vanderburgh	IN	16,844	up 0.6 percent	49%	Humana (33%)
383. Minnehaha	SD	16,809	down 0.5 percent	46%	Medica (46%)
384. Berrien	MI	16,733	up 0.2 percent	58%	Humana (45%)
385. Lebanon	PA	16,582	up 2.3 percent	57%	Highmark/BCBS (40%)
386. Sheboygan	WI	16,562	up 2.4 percent	63%	UnitedHealthcare (39%)
387. Androscoggin	ME	16,467	up 0.8 percent	70%	Martin's Point Health Care, Inc. (39%)
388. Washington	AR	16,406	up 2.5 percent	48%	Humana (36%)
389. Maui	HI	16,339	up 1.0 percent	65%	Kaiser Permanente (29%)
390. Fond du Lac	WI	16,318	up 3.1 percent	71%	Network Health, Inc. (60%)
391. Tangipahoa	LA	16,226	up 2.6 percent	66%	UnitedHealthcare (41%)
392. Hall	GA	16,174	up 5.9 percent	54%	Humana (38%)
393. Allegan	MI	16,174	up 2.5 percent	76%	Corewell Health (68%)
394. Peoria	IL	16,067	up 1.3 percent	52%	Humana (46%)
395. Cochise	AZ	16,052	up 1.7 percent	50%	Centene/Wellcare (40%)
396. Comal	TX	16,052	up 7.2 percent	47%	Humana (42%)
397. Fairfield	OH	15,984	up 3.2 percent	63%	Trinity Health Corporation (31%)
398. Mesa	CO	15,962	down 0.4 percent	50%	Humana (51%)
399. Oswego	NY	15,858	up 3.3 percent	65%	UnitedHealthcare (43%)
400. Scott	IA	15,743	up 2.2 percent	50%	Aetna/CVS (47%)
401. Josephine	OR	15,733	up 2.4 percent	60%	Regence/BCBS (28%)
402. Wright	MN	15,729	up 2.4 percent	68%	BCBS Minnesota (54%)
403. Pickens	SC	15,704	up 3.0 percent	55%	Humana (45%)
404. Jackson	MS	15,680	up 3.1 percent	51%	Humana (51%)
405. Rensselaer	NY	15,674	up 3.6 percent	62%	Lifetime Healthcare, Inc. (45%)
406. Livingston	LA	15,650	up 2.8 percent	72%	Humana (52%)
407. Greene	OH	15,643	up 2.8 percent	53%	Elevance/Anthem/BCBS (32%)
408. Rockland	NY	15,610	up 4.4 percent	34%	Aetna/CVS (29%)
409. Calcasieu	LA	15,539	up 5.6 percent	46%	Humana (51%)
410. Lawrence	PA	15,519	up 1.6 percent	75%	Aetna/CVS (36%)
411. Delaware	OH	15,410	up 5.2 percent	52%	Aetna/CVS (31%)
412. Jackson	MI	15,400	up 5.6 percent	60%	Humana (31%)
413. Beaufort	SC	15,331	up 1.2 percent	35%	UnitedHealthcare (34%)
414. Schuylkill	PA	15,282	up 3.2 percent	48%	Risant Health, Inc. (29%)
415. Newport News City	VA	15,246	up 3.4 percent	51%	Humana (42%)
416. Kenton	KY	15,205	up 3.6 percent	61%	Humana (48%)
417. Clark	OH	15,166	up 3.5 percent	64%	UnitedHealthcare (29%)
418. Ulster	NY	15,071	up 3.7 percent	44%	MVP Health Care, Inc. (33%)
419. Pitt	NC	15,020	up 4.7 percent	57%	UnitedHealthcare (41%)
420. Santa Fe	NM	14,991	up 1.6 percent	45%	UnitedHealthcare (30%)
421. Kenosha	WI	14,966	up 3.5 percent	56%	UnitedHealthcare (44%)
422. Anne Arundel	MD	14,960	down 2.3 percent	22%	CareFirst/BCBS (27%)
423. Okaloosa	FL	14,910	up 4.2 percent	35%	UnitedHealthcare (49%)
424. Johnson	IN	14,889	up 5.4 percent	53%	UnitedHealthcare (40%)
425. Hendricks	IN	14,888	up 5.3 percent	54%	UnitedHealthcare (41%)
426. Lycoming	PA	14,884	up 3.6 percent	58%	Risant Health, Inc. (38%)
427. Williamson	TN	14,818	up 1.3 percent	47%	HCSC/BCBS (39%)
428. Mayaguez	PR	14,782	up 1.0 percent	–	MHH Healthcare, L.P. (71%)
429. Wilson	TN	14,766	up 2.7 percent	56%	HCSC/BCBS (42%)
430. Wayne	NY	14,726	no change	78%	Lifetime Healthcare, Inc. (71%)
431. Monroe	PA	14,715	up 4.5 percent	47%	Aetna/CVS (24%)
432. Livingston	MI	14,698	up 4.8 percent	61%	BCBS Michigan (33%)
433. Tuscaloosa	AL	14,679	up 2.0 percent	64%	Humana (32%)
434. Tolland	CT	14,612	up 3.5 percent	–	Aetna/CVS (32%)
435. Madison	IN	14,461	up 3.8 percent	63%	Humana (34%)
436. Florence	SC	14,449	up 2.1 percent	48%	UnitedHealthcare (43%)
437. Rock Island	IL	14,403	up 1.6 percent	62%	Aetna/CVS (57%)
438. Rock	WI	14,398	up 0.3 percent	53%	UnitedHealthcare (31%)
439. Franklin	PA	14,394	up 1.7 percent	45%	Aetna/CVS (39%)
440. Wyandotte	KS	14,376	up 2.1 percent	65%	UnitedHealthcare (41%)
441. Ouachita	LA	14,268	up 2.0 percent	52%	Louisiana Health Service & Indemnity Company (31%)
442. Columbiana	OH	14,217	up 2.5 percent	63%	UnitedHealthcare (24%)
443. Bradley	TN	14,189	up 2.6 percent	60%	BCBS Tennessee (41%)
444. Scott	MN	14,126	up 2.5 percent	67%	BCBS Minnesota (53%)
445. Henderson	NC	14,033	up 2.6 percent	48%	UnitedHealthcare (44%)
446. Somerset	NJ	14,010	up 5.0 percent	40%	UnitedHealthcare (43%)
447. Guadalupe	TX	13,897	up 6.0 percent	48%	UnitedHealthcare (41%)
448. Montgomery	TN	13,870	up 4.7 percent	44%	UnitedHealthcare (27%)
449. Manitowoc	WI	13,709	up 2.2 percent	66%	Network Health, Inc. (40%)
450. Hays	TX	13,661	up 5.1 percent	52%	Humana (45%)
451. Sebastian	AR	13,639	up 2.4 percent	52%	Humana (49%)
452. Sevier	TN	13,637	up 2.9 percent	61%	Humana (51%)
453. Yamhill	OR	13,568	up 1.4 percent	63%	UnitedHealthcare (49%)
454. Dorchester	SC	13,557	up 4.7 percent	44%	Humana (35%)
455. Houston	AL	13,542	up 3.8 percent	63%	UnitedHealthcare (38%)
456. Yellowstone	MT	13,484	up 5.9 percent	39%	Humana (67%)
457. Cleveland	NC	13,477	up 3.1 percent	63%	UnitedHealthcare (35%)
458. Calhoun	MI	13,450	up 2.3 percent	58%	Corewell Health (26%)
459. Garland	AR	13,342	up 2.7 percent	49%	UnitedHealthcare (38%)
460. El Dorado	CA	13,311	down 5.4 percent	48%	Kaiser Permanente (65%)
461. Skagit	WA	13,210	up 2.5 percent	48%	UnitedHealthcare (55%)
462. Loudoun	VA	13,209	up 3.4 percent	39%	UnitedHealthcare (29%)
463. Wood	WI	13,143	up 0.8 percent	68%	Marshfield Clinic Health System, Inc. (69%)
464. Richland	OH	13,095	up 5.0 percent	54%	UnitedHealthcare (30%)
465. Etowah	AL	13,026	up 2.9 percent	67%	BCBS Alabama (25%)
466. Grayson	TX	12,903	up 4.1 percent	49%	UnitedHealthcare (60%)
467. Hampton City	VA	12,884	up 3.4 percent	51%	Humana (44%)
468. Somerset	PA	12,883	up 2.3 percent	73%	UPMC Health System (54%)
469. Calhoun	AL	12,876	up 3.2 percent	59%	UnitedHealthcare (27%)
470. La Crosse	WI	12,772	down 4.5 percent	56%	University of Wisconsin Hospitals and Clincs Autho (61%)
471. Jasper	MO	12,758	up 3.3 percent	52%	Humana (32%)
472. Ascension	LA	12,744	up 2.2 percent	74%	Humana (49%)
473. Forsyth	GA	12,741	up 1.1 percent	51%	Humana (34%)
474. Monroe	MI	12,686	up 5.3 percent	63%	Humana (29%)
475. Kent	DE	12,664	up 4.3 percent	35%	UnitedHealthcare (48%)
476. Gregg	TX	12,642	up 4.3 percent	55%	Humana (40%)
477. San Luis Obispo	CA	12,567	down 1.0 percent	25%	Alignment Health (45%)
478. Parker	TX	12,560	up 3.9 percent	48%	UnitedHealthcare (59%)
479. Indiana	PA	12,547	up 2.3 percent	77%	UPMC Health System (47%)
480. Northumberland	PA	12,546	up 2.4 percent	60%	Risant Health, Inc. (63%)
481. Greene	TN	12,509	up 2.3 percent	63%	Humana (41%)
482. Caldwell	NC	12,459	up 3.1 percent	67%	UnitedHealthcare (38%)
483. Guaynabo	PR	12,447	down 0.9 percent	–	MHH Healthcare, L.P. (54%)
484. Douglas	GA	12,441	up 5.0 percent	65%	Humana (33%)
485. Orangeburg	SC	12,392	up 1.2 percent	61%	UnitedHealthcare (58%)
486. Putnam	FL	12,385	up 3.4 percent	59%	Humana (58%)
487. Windham	CT	12,378	up 2.0 percent	–	Aetna/CVS (34%)
488. Coweta	GA	12,352	up 4.7 percent	58%	Humana (39%)
489. Miami	OH	12,348	up 4.2 percent	56%	Elevance/Anthem/BCBS (33%)
490. Kaufman	TX	12,312	up 6.2 percent	57%	UnitedHealthcare (64%)
491. Steuben	NY	12,295	up 3.0 percent	65%	UnitedHealthcare (30%)
492. St. Clair	AL	12,248	up 3.5 percent	71%	Triton Health Systems, L.L.C. (27%)
493. Grand Traverse	MI	12,235	up 3.9 percent	66%	Corewell Health (56%)
494. Dubuque	IA	12,233	up 3.4 percent	63%	Medical Associates Clinic, P.C. (84%)
495. Tuscarawas	OH	12,210	up 4.2 percent	65%	Elevance/Anthem/BCBS (30%)
496. Imperial	CA	12,197	up 7.7 percent	41%	Champion Health Plans-USA, LLC. (33%)
497. Surry	NC	12,179	up 1.3 percent	71%	UnitedHealthcare (59%)
498. Santa Barbara	CA	12,177	up 3.7 percent	22%	UnitedHealthcare (38%)
499. Wayne	OH	12,177	up 2.1 percent	58%	Humana (19%)
500. Onslow	NC	12,159	up 9.3 percent	41%	UnitedHealthcare (63%)

Source: CMS, individual Medicare Advantage plans, September 2026. Share of Medicare: CMS Geographic Variation file, 2024. The leading carrier counts individual plans only.

UnitedHealthcare and Humana by county

In September 2026, UnitedHealthcare and Humana together held 75% or more of labelled members in 834 of the 3,161 counties in the contract file. Those counties hold 10.3% of labelled members. If members with no carrier label stay in the count, the number is 818.

Contract file · September 2026

CMS contract file, all Medicare Advantage contracts, employer group plans included. Share is of labelled members. This is a different basis from the table above.

At 90% or more, the count is 288.

The lists below skip counties with fewer than 10,000 labelled members, where one plan can set the share.

Most dominant: counties where UnitedHealthcare and Humana hold the largest combined share, September 2026
County	UHC + Humana share	Leader	Leader share	Labelled members
Putnam, FL	96%	Humana	57%	12,916
Jefferson, LA	93%	Humana	53%	67,661
Taylor, TX	92%	UnitedHealthcare	83%	12,061
Kaufman, TX	91%	UnitedHealthcare	65%	14,725
Orleans, LA	89%	UnitedHealthcare	45%	47,922
Nueces, TX	88%	UnitedHealthcare	61%	44,117
Grayson, TX	88%	UnitedHealthcare	63%	15,691
Benton, WA	88%	UnitedHealthcare	53%	13,572
Alachua, FL	88%	Humana	56%	22,100
Strafford, NH	87%	Humana	51%	10,910

Most competitive: counties where UnitedHealthcare and Humana hold the smallest combined share, September 2026
County	UHC + Humana share	Leader	Leader share	Labelled members
Bayamon, PR	0%	MHH Healthcare, L.P.	47%	38,623
Ponce, PR	0%	MHH Healthcare, L.P.	41%	31,031
Carolina, PR	0%	MHH Healthcare, L.P.	48%	30,475
Caguas, PR	0%	MHH Healthcare, L.P.	58%	26,901
Arecibo, PR	0%	MHH Healthcare, L.P.	49%	20,977
Mayaguez, PR	0%	MHH Healthcare, L.P.	68%	17,155
Guaynabo, PR	0%	MHH Healthcare, L.P.	48%	16,239
Toa Baja, PR	0%	MHH Healthcare, L.P.	53%	15,159
Humacao, PR	0%	MHH Healthcare, L.P.	75%	12,674
Aguadilla, PR	0%	MHH Healthcare, L.P.	69%	11,871

CMS contract file, September 2026. Counties with 10,000 or more labelled members. Leaders here are by contract-file members, so they can differ from the table above.

Questions about county enrollment

Which counties have the most Medicare Advantage members?

The table on this page ranks counties by individual Medicare Advantage members in September 2026. 159 counties hold half of the 30.15 million members.

Do these counts include employer group plans?

No. County counts here are individual plans. Group plans a retiree gets through a former employer are left out. State and carrier pages count them.

What does MA share of Medicare mean?

It is the share of people with Medicare who were in Medicare Advantage in a CMS file from 2024. It is older than the member counts. Do not divide the counts by it.

How much of the market do UnitedHealthcare and Humana hold in a county?

Together they held 75% or more of labelled members in 834 counties in September 2026. That uses the CMS contract file, a different basis from the member counts in the table.

Cite and download

Cite this page

Senior Deal Club Standards Desk. Medicare Advantage Enrollment by County. Data as of September 2026. Source: CMS Medicare Advantage monthly enrollment, individual plans. https://www.seniordealclub.com/medicare-advantage/enrollment/counties

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