Welcome to the Reagan County Texas AgriLife Extension website. Reagan County is located on the northwestern edge of the Edwards Plateau and the southeastern edge of the Llano Estacado. It is bordered on the west by Upton County, on the north by Glasscock County, on the east by Sterling, Tom Green and Irion Counties, and on the south by Crockett County. Reagan County is 1173 square miles. The elevation ranges from 2,406 to 2,953 feet above sea level. Big Lake is located 74 miles from San Angelo and 74 miles from Midland in the southeastern part of the county. It is the only incorporated city in Reagan County.