Duncanville is a city in southwestern Dallas County, Texas, United States. Duncanville's population was 40,706 at the 2020 census. The city is part of the Best Southwest area, which includes Duncanville, Cedar Hill, DeSoto, and Lancaster.
Settlement of the area began in 1845, when Illinois resident Crawford Trees purchased several thousand acres south of Camp Dallas. In 1880, the Chicago, Texas, and Mexican Central Railway reached the area and built Duncan Switch, named for a line foreman. Charles P. Nance, the community's first postmaster, renamed the settlement Duncanville in 1882. By the late 19th century, Duncanville was home to a dry-goods stores, a pharmacy, a domino parlor, and a school. Between 1904 and 1933, the population of Duncanville increased from 113 to more than 300.
During World War II, the Army Air Corps established a landing field for flight training on property near the present-day intersection of Main St and Wheatland Road.