Which hospital has been operating longer, Providence Hospital or MedStar National Rehabilitation Hospital? 
Providence Hospital (Washington, D.C.):  Founded in 1861, it is the longest continuously operating hospital in the District. MedStar National Rehabilitation Hospital: MedStar National Rehabilitation Network (MedStar NRH) is located in Washington, D.C., and specializes in treating persons with physical disabilities, including spinal cord injury, brain injury, stroke, arthritis, amputation, multiple sclerosis, post-polio syndrome, orthopedic, and other neurological conditions.
i don't know