Glenn Dale is an unincorporated area and census-designated place (CDP) in Prince George's County, Maryland, United States. The population was 12,609 at the 2000 census. Glenn Dale is home to the Glenn Dale Hospital, an abandoned sanitorium. Glenn Dale is located at 38°58′58″N 76°48′24″W / 38.98278°N 76.80667°W / 38.98278; -76.80667 (38.982902, -76.806748). According to the United States Census Bureau, the CDP has a total area of 7.4 square miles (19.1 km²), all of it land.