Pearsall, the county seat of Frio County, is on Interstate Highway 35 and the Missouri Pacific Railroad fifty-five miles southwest of San Antonio in the central part of the county. In the 1870s wagon trains stopped at a well on a large sheep ranch when they traveled the road from Frio Town to Pleasanton; this well was known as Waggoner's (Wagner's) Well. On February 6, 1882, the International-Great Northern Railroad gained control of 2,000 acres of land around the well. An affiliate, the New York and Texas Land Company, allowed them to circumvent Texas laws limiting railroad ownership of land, and, on February 15, 1882, they platted the townsite of Pearsall, named after the vice president of the railroad, Thomas W. Pearsall, east of the newly laid railroad tracks opposite Waggoner's Well.
A general exodus of people and businesses from Frio Town ensued, and a tent community grew up around the railroad depot. Prospective buyers of town lots arrived on advertised train tours from San Antonio. By 1884 Pearsall was the new county seat of Frio County and had 700 residents, twenty businesses, three hotels, three churches, a district school, and a weekly newspaper known as the Pearsall News.
By 1890, despite a fire that devastated most of its downtown district, Pearsall had an estimated population of 1,000, Methodist, Baptist, and Christian churches, a college called Frio College headed by B. C. Hendricks, two newspapers (the Sun and the News), a corn mill, and a cotton gin. In the early 1890s the mercantile block in downtown Pearsall, established by the partnership of C. H. Beever and George Hindes, became one of the largest general merchandise operations between San Antonio and Laredo.
In 1907 Hindes helped organize the Frio Cotton Oil Company of Pearsall, and Beever helped organize the Pearsall Artesian Well Company, which provided the community with its first electric service. The Pearsall People's State Bank was organized in 1908. The city incorporated with a mayor-council form of city government in 1909, and the Pearsall Water, Ice, and Electric Company was organized in 1910. By 1914 Pearsall had an estimated population of 2,000, a variety of churches, telephone connections, ten large mercantile establishments, the Pearsall National Bank, two drugstores, four confectioneries, two barbershops, an automobile garage, a photographer, two newspapers, two millinery stores, three hotels, three cotton gins, a cottonseed oil mill, a wholesale grain store, an electric plant, the Laurel Opera House (with a seating capacity of 500 and more than seventy-five electric lights), a bakery and restaurant, two livery barns, a twenty-seven-piece concert band, and several social clubs. In 1936 Pearson had an estimated population of 2,536 and forty-one businesses.
Oil was discovered in the 1930s, natural gas was introduced in 1945, and many of Pearsall's avenues were paved in 1947. The town had an estimated population of 4,500 and eighty businesses by 1949; in 1970 it had an estimated population of 5,109 and 128 businesses. The Frio Pioneer Jail Museum, housed in the original county jail built in 1884, was formally dedicated in ceremonies addressed by United States Representative Henry B. Gonzalez and Ollie Taylor, woman sheriff of Frio County, on July 3, 1976. In 1980 Pearsall had an estimated population of 6,453 and 192 business operations. In 1990 the estimated population was 9,355, and Pearsall had six public schools, a student enrollment of 2,400, thirteen churches representing ten denominations, and a public library housing over 23,000 volumes. The surrounding country is a prime hunting location, and Pearsall holds annual festivities including a Wild Game Dinner. In the early 1990s the town experienced an oil boom led by Oryx Energy, which began drilling in the Pearsall field in September 1989. Increased exploration contributed to the revitalization of Pearsall's economy. In 2000 the population was 7,157.