Triangle is a census-designated place (CDP) in southeastern Prince William County, Virginia, United States. The population was 9,589 at the 2020 census. it is approximately 32 miles southwest of Washington, D.C.
Geography
According to the U.S. Census Bureau, Triangle has a total area of 7.7 square miles (3.0 km<sup>2</sup>), of which 7.3 square miles (2.8 km<sup>2</sup>) is land and 0.5 square miles (0.2 km<sup>2</sup>) is water.