According to a report this month from the Government Accountability Office (GAO), small "critical access" hospitals often are the only source of health care in rural communities. While they provide emergency mental health care, only some provide other in- and outpatient psychiatric care. Medicare generally pays these hospitals at cost, but most inpatient psychiatric services aren't eligible for cost-based payment.
The report can be obtained at https://www.gao.gov/assets/gao-23-105950.pdf.