Started as a small ranching community in the late 1880s, Big Lake owes its original existence to the Kansas City, Mexico and Orient Railway, which passed through the area in 1912, as it was extended from Sherwood, west of San Angelo, to Girvin and beyond the Pecos River. The growth from the railroad, coupled with that from the Santa Rita discovery well in 1923, allowed it, in 1925, to take over the position of county seat from Stiles, a pioneer ranching community established in 1894 on Centrailia Draw, about 20 miles to the north. The main highway through the area, US 67, was extended through the region in 1934, on the way to a termination in Presidio. The city's current existence is based on agriculture (some farming, but mostly ranching) and oil and gas service and production throughout the area.