Dawson County is a county in the U.S. state of Texas. As of the 2020 census, its population was 12,456. The county seat is Lamesa. The county was created in 1876 and later organized in 1905. It is named for Nicholas Mosby Dawson, a soldier of the Texas Revolution. Dawson County comprises the Lamesa, TX Micropolitan Statistical Area, and it is, by population, the smallest Micropolitan Statistical Area in the United States.