Naval Air Station Patuxent River, also known as NAS Pax River, is a United States naval air station located in St. Mary’s County, Maryland, on the Chesapeake Bay near the mouth of the Patuxent River. It is home to Headquarters, Naval Air Systems Command, the U.S. Naval Test Pilot School, the Atlantic Test Range, Patuxent River Naval Air Museum, and serves as a center for test and evaluation and systems acquisition relating to naval aviation.