Bethesda () is an unincorporated, census-designated place in southern Montgomery County, Maryland, United States. Located just northwest of Washington, D.C., it is a major business and government center of the Washington metropolitan region and a national center for medical research. According to the 2020 census, the community had a total population of 68,056. It takes its name from a local church, the Bethesda Meeting House (1820, rebuilt 1849), which in turn took its name from Jerusalem's Pool of Bethesda.