Medicare Advantage in Washington County, Idaho
1,700 people in Washington County, Idaho were enrolled in Medicare Advantage in October 2026, 48.9% of 3,477 eligible beneficiaries (−1.5 pts since October 2025). Trinity Health Corporation is the largest parent organization with 32% of reported enrollment; 7 parent organizations have 11 or more members and the HHI is 2,628 (highly concentrated). HRSA classifies the county as fully rural. For 2027, 681 members here are in plans that terminate or leave the county, and Trinity Health Corporation leaves. MA plans offered go from 18 to 13.
Parent organizations in Washington County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| Trinity Health Corporation | 545 | +434 | 32.4% |
| Humana Inc. | 531 | +132 | 31.6% |
| UnitedHealth Group, Inc. | 379 | +29 | 22.5% |
| Gemstone Holdings, Inc. | 110 | −617 | 6.5% |
| Molina Healthcare, Inc. | 92 | −2 | 5.5% |
| CVS Health Corporation | 13 | +1 | 0.8% |
| Mitchell Family Office | 12 | new | 0.7% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 494 beneficiaries in Washington County were assigned to 11 Medicare Shared Savings Program ACOs, 39.9% of assignable Original Medicare beneficiaries. Together, roughly 69% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.