Dumbarton is a census-designated place in Henrico County, Virginia, United States. The population was 7,879 at the 2010 census. Dumbarton is located at 37°36′33″N 77°30′22″W / 37.60917°N 77.50611°W. According to the United States Census Bureau, the CDP has a total area of 1.9 square miles, of which 1.9 square miles is land and 0.019 square mil…Dumbarton is a census-designated place in Henrico County, Virginia, United States. The population was 7,879 at the 2010 census. Dumbarton is located at 37°36′33″N 77°30′22″W / 37.60917°N 77.50611°W. According to the United States Census Bureau, the CDP has a total area of 1.9 square miles, of which 1.9 square miles is land and 0.019 square miles, or 0.99%, is water.