The central region of Texas covers the state's three largest cities: Houston, Dallas-Fort Worth and San Antonio. The limestone terrain of Texas Hill Country lies in Central Texas, as do the state's three largest rivers, the Trinity, the Brazos and the Colorado. The value of all farms, ranches, hunting land and other land for sale in Texas's Mills County recently was approximately $140 million, representing a total of 15,325 acres of land for sale in Mills County. Mills County ranks 137th out of 254 counties in the state for the total acreage of land currently advertised for sale. Goldthwaite had the most land for sale. Agriculture and farming drives the Mills County economy, with 870 farms recorded in the county during the U.S. Census in 2012. Farming activities in Mills County generate annual revenues of $4 million, the majority of which comes from livestock products. Mills County is Texas's 213th biggest county (749 square miles). It's located in the Hill Country North Texas region of the state.