In 38 U.S. counties, three in four Medicare beneficiaries are enrolled in Medicare Advantage, according to data from KFF.
In 2024, 54% of Medicare beneficiaries are enrolled in MA plans. Rates of MA enrollment vary by state, from a high of 63% in Michigan to a low of 2% in Alaska.
Monroe County, N.Y., where Rochester is located, has the highest rate of MA penetration in the U.S., with 82% of Medicare eligibles enrolled in an MA plan.
Here are the counties where more than 75% of the Medicare market is enrolled in MA:
Monroe County, N.Y.
MA penetration: 82%
MA enrollment: 128,459
Starr County, Texas
MA penetration: 81%
MA enrollment: 7,750
Miami-Dade County, Fla.
MA penetration: 80%
MA enrollment: 379,024
Ottawa County, Mich.
MA penetration: 79%
MA enrollment: 44,440
St. John the Baptist County, La.
MA penetration: 79%
MA enrollment: 6,283
Rockingham County, N.C.
MA penetration: 78%
MA enrollment: 18,260
St. Charles County, La.
MA penetration: 78%
MA enrollment: 7,290
Erie County, N.Y.
MA penetration: 77%
MA enrollment: 146,584
Jefferson County, La.
MA penetration: 77%
MA enrollment: 65,283
Clayton County, Ga.
MA penetration: 77%
MA enrollment: 26,568
Randolph County, N.C.
MA penetration: 77%
MA enrollment: 23,815
Ontario County, N.Y.
MA penetration: 77%
MA enrollment: 20,530
Allegan County, Mich.
MA penetration: 77%
MA enrollment: 19,012
Newaygo County, Mich.
MA penetration: 77%
MA enrollment: 9,578
Calumet County, Wis.
MA penetration: 77%
MA enrollment: 7,252
El Paso County, Texas
MA penetration: 76%
MA enrollment: 101,767
Kent County, Mich.
MA penetration: 76%
MA enrollment: 85,113
Hidalgo County, Texas
MA penetration: 76%
MA enrollment: 83,493
Cameron County, Texas
MA penetration: 76%
MA enrollment: 49,232
Niagara County, N.Y.
MA penetration: 76%
MA enrollment: 37,241
Beaver County, Pa.
MA penetration: 76%
MA enrollment: 30,930
Outagamie County, Wis.
MA penetration: 76%
MA enrollment: 27,813
Wayne County, N.Y.
MA penetration: 76%
MA enrollment: 16,819
Armstrong County, Pa.
MA penetration: 76%
MA enrollment: 12,916
Livingston County, N.Y.
MA penetration: 76%
MA enrollment: 10,575
Gadsden County, Fla.
MA penetration: 76%
MA enrollment: 7,708
Oconto County, Wis.
MA penetration: 76%
MA enrollment: 7,644
Westmoreland County, Pa.
MA penetration: 75%
MA enrollment: 69,373
Osceola County, Fla.
MA penetration: 75%
MA enrollment: 49,831
Orleans County, La.
MA penetration: 75%
MA enrollment: 45,761
Muskegon County, Mich.
MA penetration: 75%
MA enrollment: 29,895
Davidson County, N.C.
MA penetration: 75%
MA enrollment: 27,901
Cambria County, Pa.
MA penetration: 75%
MA enrollment: 27,049
Franklin County, Mo.
MA penetration: 75%
MA enrollment: 18,202
Maverick County, Texas
MA penetration: 75%
MA enrollment: 7,527
Chilton County, Ala.
MA penetration: 75%
MA enrollment: 7,038
Willacy County, Texas
MA penetration: 75%
MA enrollment: 2,599
Lowndes County, Ala.
MA penetration: 75%
MA enrollment: 2,103