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.

HR 4258 would expand Medicare's critical access hospital (CAH) program to include certain hospitals located on Indian reservations. Starting August 1, 2025, states could designate qualifying reservation hospitals as CAHs if they are more than 35 miles (or 15 miles in mountainous areas) from another reservation hospital or an Indian Health Service/tribal facility. This change would allow these hospitals to receive Medicare reimbursement under CAH rules, which provide higher payment rates for rural facilities. The bill also permits such hospitals to establish psychiatric or rehabilitation units without being restricted by the usual bed count limits for CAHs. This directly affects hospitals on tribal lands seeking improved Medicare funding access.