Duncanville is a city in southern Dallas County, Texas, in the United States. Duncanville's population was 38,524 at the 2010 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.