Greenbelt is a city in Prince George's County, Maryland, United States, and a suburb of Washington, D.C. At the 2020 census, the population was 24,921. Greenbelt is the first and the largest of the three experimental and controversial New Deal Greenbelt Towns, the others being Greenhills, Ohio, and Greendale, Wisconsin. Greenbelt was planned and built by the federal government as an all-white town.