New Carrollton is a city located in central Prince George's County, Maryland, in the United States. As of the 2010 census, population was 12,135. New Carrollton is 12 miles (19 km) east of the center of Washington, D.C. It is built on the former estate of a horse racing figure, Edward L. Mahoney. After Mahoney's death in 1957, the land was acquired by developer Albert W. Turner, who sought to create a planned suburb.