Greenbelt is a city in Prince George's County, Maryland, United States. Contained within today's City of Greenbelt is the historic, planned community now known locally as "Old Greenbelt." Unlike most towns that develop gradually over a long period of time, Greenbelt was the first of three "green towns" built from scratch by Rexford Guy Tugwell's Resettlement Administration as part of President Franklin Roosevelt's New Deal. The Goddard Space Flight Center of the National Aeronautics and Space Administration is located there, as is Greenbelt Park. Population: 21,456 Geographic Size: 6.0 sq miles County: Prince Georges School information Utility companies in the state County assessment page To learn more about Greenbelt, MD, visit greenbelt.com and greenbeltmd.gov.