A critical access hospital (CAH) is a small, federally designated hospital in a rural area that receives special Medicare reimbursement to keep it financially viable. The designation exists because many rural communities are too far from larger medical centers, and without financial support, their local hospitals would close. As of January 2026, 1,381 critical access hospitals operate across the United States, forming the backbone of healthcare in areas where the nearest alternative may be 35 miles or more away.
Requirements for the Designation
To qualify as a critical access hospital, a facility must meet several criteria set by the Centers for Medicare and Medicaid Services (CMS). The most defining requirements are size and location. A CAH can maintain no more than 25 inpatient beds, and it must be located more than a 35-mile drive from the nearest hospital on primary roads. In mountainous terrain or areas with only secondary roads, that threshold drops to 15 miles. Some hospitals certified before January 1, 2006, were grandfathered in under a “necessary provider” designation by their state, even if they didn’t meet the strict distance requirement.
Beyond size and location, every CAH must provide emergency services 24 hours a day. Acute care patients cannot stay longer than 96 hours on average per year, which keeps the facility focused on stabilization and short-term treatment rather than extended hospitalization. In addition to the 25 acute care beds, a CAH can operate a psychiatric unit and a rehabilitation unit of up to 10 beds each, giving some flexibility for specialized care.
How CAHs Are Paid Differently
The financial model is what makes the CAH designation matter. Most hospitals get paid by Medicare under a prospective payment system, meaning they receive a fixed amount based on the patient’s diagnosis regardless of what treatment actually costs. Critical access hospitals operate under a completely different arrangement: Medicare reimburses them at 101 percent of their reasonable costs. That extra one percent above break-even provides a thin but essential margin that helps these small facilities stay open in communities where patient volume is too low to survive on standard Medicare rates.
This cost-based reimbursement also extends to swing bed services. A swing bed program allows a CAH to use the same physical beds for both acute care and post-hospital skilled nursing care, depending on what patients need at any given time. Rather than transferring a recovering patient to a nursing facility that might be an hour away, the hospital can keep them and provide skilled nursing-level care in the same bed. Medicare covers these services under Part A, and for CAHs specifically, the payment remains at 101 percent of reasonable cost rather than the lower rates that apply to other small hospitals with swing bed agreements.
What Services CAHs Typically Provide
Critical access hospitals are not full-service medical centers. They handle emergency stabilization, short-term acute care, basic lab work, imaging, and outpatient services. Many also provide primary care clinics attached to the hospital. The 96-hour average length of stay requirement means patients with complex conditions or those needing surgery beyond what the facility can handle will be stabilized and transferred to a larger hospital.
The swing bed capability is particularly valuable in rural areas where skilled nursing facilities are scarce. If you’ve had a hip replacement at a regional hospital and need several days of rehabilitation afterward, a CAH near your home can provide that post-acute care closer to your family. To qualify, you need a prior hospital stay of at least three consecutive days covered by Medicare Part A.
Why Rural Hospitals Need This Protection
The CAH program was created in 1997 in response to a wave of rural hospital closures. The problem hasn’t gone away. Between January 2005 and July 2024, 192 out of roughly 2,075 rural hospitals either closed entirely or converted to a more limited designation. When a rural hospital closes, the effects on the surrounding community are measurable and serious. Patients face longer travel distances to reach care, emergency transport times increase, and most research on hospital closures has found higher mortality rates in the affected communities.
For many small towns, losing the hospital also means losing the largest employer and a key reason families and businesses stay in the area. The CAH designation is essentially a policy tool that trades higher per-patient Medicare spending for the preservation of local healthcare access.
How CAHs Compare to Rural Emergency Hospitals
A newer option called the Rural Emergency Hospital (REH) became available in 2023 as an alternative for struggling rural facilities. The key difference is that REHs cannot provide inpatient care. They offer emergency department services, observation stays of up to 24 hours on average, and outpatient services, but patients who need to be admitted must be transferred elsewhere. An REH can operate a distinct skilled nursing facility unit, but it cannot function as a traditional hospital with overnight acute care beds.
For communities where keeping a full inpatient hospital running isn’t feasible, converting to an REH preserves emergency access. But researchers have raised concerns that shifting rural hospitals toward emergency-only models still results in a net decline in essential services, particularly for older adults who rely on local inpatient and post-acute care. A critical access hospital, by contrast, maintains the full range of short-term inpatient services alongside its emergency department, making it the more comprehensive rural designation when a community can support it.