H.R. 4258 — To amend title XVIII of the Social Security Act to expand the definition of critical access hospital under the Medicare program to include certain hospitals on Indian reservations.

This section expands Medicare critical access hospital (CAH) designation eligibility, effective August 1, 2025, to facilities on Indian reservations (as defined in the Indian Health Care Improvement Act) that are more than a 35-mile drive (or 15 miles in mountainous terrain or secondary-road areas) from another hospital or facility on a reservation or operated by the Indian Health Service, an Indian tribe or tribal organization, or an urban Indian organization. (As background, CAHs are small rural hospitals reimbursed by Medicare on a cost basis rather than under prospective payment systems to support healthcare access in underserved areas; standard CAH criteria generally require facilities to be in rural areas more than 35 miles—or 15 miles in certain terrain—from any hospital and limit total acute care beds to 25, with further limits on psychiatric and rehabilitation distinct part units.) Such facilities may also establish psychiatric and rehabilitation distinct part units without regard to the standard bed limitation.