Eldorado, the county seat of Schleicher County, is at the intersection of U.S. highways 190 and 277, forty-five miles south of San Angelo near the center of the county. The area was part of a grant made by the state of Texas to the Houston East and West Texas Railway Company in 1878, but the railroad laid no track there. In 1895 W. B. Silliman acquired half interest in one of the sections of land and formed a company with two other men to establish a new townsite. Silliman surveyed the site, named the new town Eldorado, opened a store, and attracted residents from nearby Verand by offering them free town lots if they would move to Eldorado. The post office at Verand was officially transferred to Eldorado in 1895, and by 1896 Eldorado had two general stores and 100 residents. The community’s first school was established in 1897. When Schleicher County was organized in 1901, Eldorado was named county seat.

The town grew quickly due to the land rushes that took place in Schleicher County between 1901 and 1905, and it thrived as a commercial center for area ranchers. Residents hoped that a rail line would be extended to Eldorado from San Angelo, but the railroad company went into receivership in 1912. In 1914 Eldorado had three churches, a bank, a weekly newspaper, a variety of businesses, and a population of 500. Residents voted to incorporate in 1925 but revoked the ordinance two years later because they disliked the higher taxes and the fact that livestock within the city was required to be penned; the local Lions Club began to circulate a second petition for incorporation in January 1929, and in March of that year voters agreed, choosing a mayor-alderman form of city government. The Kansas City, Mexico and Orient Railway built a line between San Angelo and Sonora in 1930; the track passed through Eldorado and gave Schleicher County residents easy access to outside markets.

By the early 1930s Eldorado had grown to 1,404 residents and fifty-five businesses; the population rose to 1,530 by the 1940s and to 1,653 by the 1950s. West Texas Woolen Mills was established in 1941, and Eldorado became the region’s principal wool-processing center. Population estimates for the town reached a high of 2,790 in the mid-1960s, but the residents numbered fewer than 1,400 by the mid-1970s. Improved highways lessened the community’s dependence on rail service, and the Atchison, Topeka and Santa Fe Railroad abandoned its track through Eldorado in 1976. The population of Eldorado was estimated at 2,061 in 1982; in 1990 it was 2,019. The population dropped to 1,951 in 2000.