Colorado Medicare, by the Numbers

Medicare Enrollment by County

Counties covered by our city pages (26 counties, 984,182 beneficiaries). Each links to its anchor city page.

Statewide, 52.7% of beneficiaries chose Medicare Advantage in 2025, more than half, so prior authorizations, network questions, and denials worth appealing come up constantly. Counties above that line see the most of it. Colorado uses the standard federal Medigap letter plans, all regulated by the Colorado Division of Insurance under Regulation 4-3-1: there is no birthday rule or annual guaranteed-issue window, so a switch outside your six-month open enrollment can be medically underwritten, which makes timing matter, but Colorado does require insurers to sell Medigap to people under 65 who have Medicare because of a disability. About 8% of Colorado seniors live below the poverty line, the group most likely to qualify for unclaimed help: federal Extra Help and the Medicare Savings Programs Health First Colorado runs. For the full rundown, sources included, see our Colorado patient advocacy hub.