Coppell is a city in the northwest corner of Dallas County in the U.S. state of Texas. It is a suburb of Dallas and a bedroom community in the Da…Coppell is a city in the northwest corner of Dallas County in the U.S. state of Texas. It is a suburb of Dallas and a bedroom community in the Dallas–Fort Worth metroplex. Its population was 42,983 at the 2020 census. A small area in the far northern portion of the city extends into neighboring Denton County.