Medicare Advantage in Stillwater County, Montana
985 people in Stillwater County, Montana were enrolled in Medicare Advantage in October 2026, 33.9% of 2,904 eligible beneficiaries (−1.0 pts since October 2025). Humana Inc. is the largest parent organization with 89% of reported enrollment; 4 parent organizations have 11 or more members and the HHI is 8,038 (highly concentrated). HRSA classifies the county as fully rural. For 2027, 473 members here are in plans that terminate or leave the county, and Health Care Service Corporation leaves. MA plans offered go from 8 to 7.
Parent organizations in Stillwater County
| Parent organization | Members | Change since October 2025 | Share |
|---|---|---|---|
| Humana Inc. | 864 | +227 | 89.4% |
| CVS Health Corporation | 41 | −5 | 4.2% |
| Health Care Service Corporation | 33 | −21 | 3.4% |
| UnitedHealth Group, Inc. | 28 | −216 | 2.9% |
CMS suppresses county and contract counts of 10 or fewer; shares are of reported enrollment.
Value-based care alongside MA
In PY 2024, 590 beneficiaries in Stillwater County were assigned to 20 Medicare Shared Savings Program ACOs, 43.2% of assignable Original Medicare beneficiaries. Together, roughly 62% of all Medicare beneficiaries in the county are in Medicare Advantage or an MSSP ACO. See the ACOs in the MSSP Explorer.