Mason is a city in, and the county seat of, Mason County, Texas, United States. The city is an agricultural community on Comanche Creek so…Mason is a city in, and the county seat of, Mason County, Texas, United States. The city is an agricultural community on Comanche Creek southwest of Mason Mountain, on the Edwards Plateau and part of the Llano Uplift. Its population was 2,121 at the 2020 census.