Colorado City is a city in and the county seat of Mitchell County, Texas, United States. Its population was 3,991 at the 2020 census. Colorad…Colorado City is a city in and the county seat of Mitchell County, Texas, United States. Its population was 3,991 at the 2020 census. Colorado City originated as a ranger camp in 1877. It grew into a cattlemen's center and has been called "the Mother City of West Texas". The town acquired a railway station and post office in 1881 and was named the county seat. In the early 1880s it was a center for cattle shipment, with herds driven to Colorado City and loaded onto trains for shipment to the eastern markets. The population was estimated at 6,000 in 1884–1885, but dropped to 2,500 by 1890 after a drought, and dropped further with the growth of nearby San Angelo.