How far a Medicare Advantage network can send you
Medicare Advantage plans may limit members to a network of doctors and hospitals. CMS's only check on how far away that network can be is a maximum drive time, set county by county for each specialty and loosened the more rural the county. This map compares that limit with how far older residents actually live from the nearest specialist who treats Medicare patients. The gap is how much farther a plan's network can send them and still pass.
The rules loosen faster than the distances grow
Every specialty, in rural counties
The base drive-time limit for rural counties against the average drive from older rural residents to the nearest provider. Click a row to map that specialty.
How this was estimated
The rules. Maximum drive times by county and specialty come from the CMS 2026 HSD Reference File, which CMS uses to review Medicare Advantage networks under 42 CFR 422.116. Every county is one of five types (Large Metro, Metro, Micro, Rural, or Counties with Extreme Access Considerations) based on population and density, and each type has a base limit. CMS raises the limit in counties where no provider exists within the base limit. There is also a maximum distance, not shown here. A network passes if 90% of the plan's members in the county live within the limits of at least one in-network provider. Plans can also get credit for telehealth providers in many specialties and can request exceptions.
Nearest provider. Clinicians come from the CMS Doctors and Clinicians national file (everyone enrolled in Medicare, by primary specialty), placed at the center of their practice ZIP code. Primary care is internal medicine, family practice, general practice and geriatrics physicians; nurse practitioners and physician assistants are not counted. Oncology is medical, hematology/oncology and surgical oncology. Hospitals are Medicare-certified acute care and critical access hospitals, located with the Census geocoder; skilled nursing is every Medicare-certified nursing home, at CMS's coordinates.
Drive time. For each census tract, the straight-line distance from its 2020 population center to the nearest provider was converted to driving minutes with a model fitted to real routes: Times are capped at minutes. County figures are averaged over residents 65 and older (CDC/ATSDR SVI 2022, from the 2018–2022 American Community Survey).
Caveats. This compares the rules with the nearest provider of any kind, not with any plan's actual network, which can only be the same distance or farther. A provider listed in a ZIP code may not see new patients or accept a given plan. The drive model is rough for short city trips, and ZIP-code placement adds a few minutes of error, so the "past the limit" share is unreliable where limits are 10 to 20 minutes (Large Metro counties, and primary care everywhere). CMS measures access with its own travel-time data. Alaska and Connecticut counties follow the codes in CMS enrollment files.
Related: the dialysis time tax and clinical trial deserts, built with the same drive-time model. Data and build scripts: github.com/usnish/usnish.github.io.