Medicare Advantage in Warren County, Illinois
1,484 people in Warren County, Illinois were enrolled in Medicare Advantage in October 2026, 38.9% of 3,813 eligible beneficiaries (−0.6 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 33% of reported enrollment; 6 parent organizations have 11 or more members and the HHI is 2,500 (highly concentrated). HRSA classifies the county as fully rural. For 2027, 94 members here are in plans that terminate or leave the county, and Health Care Service Corporation leaves. MA plans offered go from 20 to 13.
Parent organizations in Warren County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 479 | 0 | 33.0% |
| CVS Health Corporation | 464 | −37 | 32.0% |
| Humana Inc. | 213 | +58 | 14.7% |
| Centene Corporation | 163 | +7 | 11.2% |
| Health Care Service Corporation | 94 | +31 | 6.5% |
| Molina Healthcare, Inc. | 39 | −9 | 2.7% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 473 beneficiaries in Warren County were assigned to 16 Medicare Shared Savings Program ACOs, 24.6% of assignable Original Medicare beneficiaries. Together, roughly 54% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.