Medicare Advantage in Colusa County, California
234 people in Colusa County, California were enrolled in Medicare Advantage in October 2026, 5.4% of 4,295 eligible beneficiaries (−7.2 pts since October 2025). UnitedHealth Group, Inc. is the largest parent organization with 63% of reported enrollment; 5 parent organizations have 11 or more members and the HHI is 4,338 (highly concentrated). HRSA classifies the county as fully rural. For 2027, 12 members here are in plans that terminate or leave the county, and Imperial Health Plan of California leaves.
Parent organizations in Colusa County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| UnitedHealth Group, Inc. | 137 | +5 | 62.8% |
| California Physicians' Service | 31 | −7 | 14.2% |
| Elevance Health, Inc. | 22 | −156 | 10.1% |
| Kaiser Foundation Health Plan, Inc. | 16 | 0 | 7.3% |
| Imperial Health Plan of California | 12 | new | 5.5% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 1,151 beneficiaries in Colusa County were assigned to 20 Medicare Shared Savings Program ACOs, 42.1% of assignable Original Medicare beneficiaries. Together, roughly 45% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.