Lamesa is a city in and the county seat of Dawson County, Texas, United States. The population was 8,674 at the 2020 census, down from 9,952 at the 2000 census. Located south of Lubbock on the Llano Estacado, Lamesa was founded in 1903. Most of its economy is based on cotton farming. The Preston E. Smith prison unit, named for the former governor of Texas, is located just outside Lamesa.