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MA Enrollment Explorer / States / Illinois

Medicare Advantage in Illinois: enrollment, penetration and market share

1,101,618 people in Illinois were enrolled in Medicare Advantage in October 2026. 44.0% of the state's 2,505,334 eligible Medicare beneficiaries are in Medicare Advantage, +0.02 pts since October 2025. CVS Health Corporation is the largest parent organization with 32% of reported enrollment; 22 parent organizations have 11 or more members, and the market's HHI is 2,411 (highly concentrated). Through the 2026 Annual Election Period (December to February), reported MA enrollment in Illinois changed by +5,971 (+0.6%).

44.0%MA penetration, October 2026
1.10MMA enrollees
22parent organizations (11+ members)
2,411HHI, highly concentrated
Open Illinois on the market mapMSSP ACOs in Illinois

Parent organizations in Illinois

Parent organizationMembersChangeShareShare change
CVS Health Corporation345,938+5,69431.6%−0.2 pts
Humana Inc.336,770+68,85230.7%+5.8 pts
UnitedHealth Group, Inc.220,165−5,42520.1%−0.9 pts
Health Care Service Corporation68,491−27,5806.2%−2.7 pts
Centene Corporation48,357−1,7104.4%−0.3 pts
Zing Health Consolidator, Inc19,464+2,3171.8%+0.2 pts
Molina Healthcare, Inc.15,089+9981.4%+0.1 pts
Devoted Health, Inc.14,774+6,5031.3%+0.6 pts
Lumeris Group Holdings Corporation13,889+2,7471.3%+0.2 pts
UMWA Health and Retirement Funds3,614−1990.3%−0.03 pts
Medical Associates Clinic, P.C.1,997−20.2%−0.00 pts
Elevance Health, Inc.1,867−480.2%−0.01 pts
Union Health Services, Inc.1,639+230.1%−0.00 pts
Rifkin Managed Care Holding, LLC1,104−1200.1%−0.01 pts
Longevity Health Founders, LLC961−135under 0.1%−0.01 pts
Highmark Health864+25under 0.1%+0.00 pts
Blue Cross Blue Shield of Michigan Mutual Ins. Co.853−36under 0.1%−0.01 pts
Esperanza Health Centers46+21under 0.1%+0.00 pts
Lawndale Christian Health Center45+15under 0.1%+0.00 pts
OSF Healthcare System41+23under 0.1%+0.00 pts

Change and share change are since October 2025. Shares are of reported enrollment in the CMS State/County/Contract file.

Counties

CountyMA enrolleesPenetrationLeading parent
Cook County403,21944.9%Humana Inc. 37%
DuPage County71,15437.8%Humana Inc. 43%
Will County52,79941.7%Humana Inc. 42%
Lake County47,00634.8%Humana Inc. 45%
Kane County38,39740.2%Humana Inc. 38%
Winnebago County37,66258.7%CVS Health Corporation 50%
Madison County33,63055.7%UnitedHealth Group, Inc. 42%
St. Clair County30,65855.7%UnitedHealth Group, Inc. 43%
Sangamon County27,11959.3%CVS Health Corporation 74%
McHenry County24,81937.0%Humana Inc. 43%
Champaign County19,78758.8%CVS Health Corporation 75%
Peoria County19,65151.3%Humana Inc. 41%
Rock Island County19,55859.2%CVS Health Corporation 50%
Tazewell County14,21645.4%Humana Inc. 40%
McLean County13,73944.3%CVS Health Corporation 48%
Vermilion County10,06856.5%CVS Health Corporation 63%
La Salle County9,59735.6%CVS Health Corporation 37%
Kankakee County9,40039.7%CVS Health Corporation 39%
Macon County9,30837.8%CVS Health Corporation 60%
Kendall County8,08838.9%Humana Inc. 50%
DeKalb County8,03042.5%CVS Health Corporation 50%
Stephenson County7,54262.0%CVS Health Corporation 60%
Williamson County6,21038.0%CVS Health Corporation 54%
Adams County6,04237.9%UnitedHealth Group, Inc. 60%
Henry County6,00048.3%CVS Health Corporation 48%
Whiteside County5,96440.6%UnitedHealth Group, Inc. 47%
Knox County5,90746.2%Humana Inc. 36%
Ogle County5,89547.7%CVS Health Corporation 57%
Boone County5,84451.6%CVS Health Corporation 46%
Jackson County5,71451.5%CVS Health Corporation 56%
Macoupin County5,27944.0%CVS Health Corporation 42%
Coles County5,08647.8%CVS Health Corporation 68%
Monroe County4,71553.4%UnitedHealth Group, Inc. 38%
Franklin County4,09741.8%CVS Health Corporation 40%
Jo Daviess County4,04257.3%Medical Associates Clinic, P.C. 50%
Christian County4,00148.6%CVS Health Corporation 65%
Fulton County4,00147.2%CVS Health Corporation 48%
Randolph County3,84352.5%CVS Health Corporation 44%
Grundy County3,67535.5%Humana Inc. 43%
Morgan County3,61243.5%CVS Health Corporation 57%
Lee County3,52040.1%CVS Health Corporation 50%
Livingston County3,48441.0%Humana Inc. 42%
Clinton County3,47639.4%UnitedHealth Group, Inc. 52%
Marion County3,24333.0%UnitedHealth Group, Inc. 48%
Woodford County3,21136.1%Humana Inc. 47%
Logan County2,99746.9%CVS Health Corporation 57%
Montgomery County2,92240.3%CVS Health Corporation 60%
Jefferson County2,85132.5%CVS Health Corporation 47%
McDonough County2,85146.9%CVS Health Corporation 64%
Bureau County2,83732.8%CVS Health Corporation 49%
Jersey County2,68946.2%UnitedHealth Group, Inc. 53%
Iroquois County2,41333.2%CVS Health Corporation 42%
Effingham County2,37927.8%CVS Health Corporation 68%
Piatt County2,33656.0%CVS Health Corporation 74%
Saline County2,29837.3%CVS Health Corporation 45%
Perry County2,18244.6%CVS Health Corporation 31%
Douglas County2,17951.1%CVS Health Corporation 77%
Union County2,04044.1%CVS Health Corporation 62%
Mercer County1,94645.5%UnitedHealth Group, Inc. 53%
Bond County1,83948.0%UnitedHealth Group, Inc. 47%
Carroll County1,80440.1%UnitedHealth Group, Inc. 35%
Clark County1,73643.9%CVS Health Corporation 56%
Fayette County1,73336.6%CVS Health Corporation 51%
Shelby County1,67531.2%CVS Health Corporation 67%
Menard County1,65954.5%CVS Health Corporation 66%
De Witt County1,62141.6%CVS Health Corporation 48%
Edgar County1,59735.2%CVS Health Corporation 44%
Warren County1,48438.9%UnitedHealth Group, Inc. 33%
Mason County1,47441.5%CVS Health Corporation 53%
Johnson County1,39043.2%CVS Health Corporation 63%
Hancock County1,31326.1%UnitedHealth Group, Inc. 32%
Marshall County1,24638.1%Humana Inc. 41%
Pike County1,21732.1%CVS Health Corporation 46%
Greene County1,19240.4%CVS Health Corporation 49%
Crawford County1,18525.8%CVS Health Corporation 54%
Ford County1,17134.8%CVS Health Corporation 60%
Massac County1,16030.5%CVS Health Corporation 41%
Moultrie County1,13734.0%CVS Health Corporation 72%
Cumberland County1,12941.9%CVS Health Corporation 74%
Richland County1,12128.8%CVS Health Corporation 49%
Cass County1,11641.3%CVS Health Corporation 60%
Washington County1,10731.2%UnitedHealth Group, Inc. 46%
White County1,06528.6%CVS Health Corporation 42%
Wayne County96924.8%CVS Health Corporation 46%
Lawrence County89727.0%CVS Health Corporation 44%
Clay County84225.3%CVS Health Corporation 61%
Alexander County72051.2%UnitedHealth Group, Inc. 51%
Jasper County69427.7%CVS Health Corporation 65%
Schuyler County66238.2%CVS Health Corporation 66%
Wabash County63322.1%CVS Health Corporation 45%
Henderson County61834.2%UnitedHealth Group, Inc. 43%
Hamilton County60931.3%CVS Health Corporation 50%
Pulaski County58741.8%CVS Health Corporation 50%
Stark County55740.1%CVS Health Corporation 38%
Putnam County51531.7%CVS Health Corporation 45%
Calhoun County50039.2%UnitedHealth Group, Inc. 46%
Scott County45140.8%CVS Health Corporation 73%
Gallatin County45033.3%CVS Health Corporation 37%
Pope County42535.6%CVS Health Corporation 57%
Brown County41936.6%CVS Health Corporation 67%
Edwards County34220.9%CVS Health Corporation 52%
Hardin County32932.5%CVS Health Corporation 57%