Carrizo Springs, the county seat of Dimmit County, is on U.S. Highway 83 eight miles northwest of Asherton. The name of the town comes from the local springs, which were named by the Spanish for the cane grass that once grew around them. Carrizo Springs is the oldest town in Dimmit County; it was founded in 1865 by a group of fifteen families from Atascosa County, led by Levi English, who had visited the area earlier. A second group of settlers arrived from Goliad about two years later.
The Carrizo Springs settlement was still quite small in 1880, when Dimmit County was organized. Nevertheless, as the largest and oldest community in the county, it was designated the county seat. In 1880 English donated a parcel of land for a townsite, including land designated for schools, churches, and a courthouse. The town began to grow, and the residents constructed their homes of solid, lasting materials. In 1881 a local group of Masons helped to build the first schoolhouse in Carrizo Springs, and two years later construction began on a courthouse. A newspaper, the Carrizo Springs Javelin, began operations in 1884. By 1885 Carrizo Springs had two churches, at least one grocery, a livery stable, a harness and boot shop, and a population of 900. By 1892 the town also had two druggists, a steam gristmill and gin, and a nursery.
Until 1900 the local economy relied primarily on sheep and cattle ranching, but when artesian water was discovered to be a cheap source of irrigation, new settlers arrived and land prices rose. By 1904 there were thirty artesian wells in the Carrizo Springs area, with average flows ranging from forty to 300 gallons of water a minute, irrigating over 1,000 acres of new cropland.
In 1910 the San Antonio, Uvalde and Gulf Railroad opened a spur into Carrizo Springs; that same year the town incorporated. By 1915 the community had grown to 1,200 residents, who supported three churches, two banks, two hotels, an ice plant, several grocery stores, two real estate businesses, and a title company. By 1916 Carrizo Springs had electricity. In the early 1920s a period of drought and low agricultural prices depressed most Dimmit County farmers, but between 1925 and 1927 seventeen new businesses opened and fifty-five new homes were built. The old courthouse was remodeled and enlarged, and ten blocks of the town's business district were paved. By 1928 Carrizo Springs had a population of 2,500. In 1936 the town's population was 2,171. By 1943 the town had a population of 2,494 and sixty-two businesses, and in 1952 it had 4,343 residents and 130 businesses. By the 1980s Carrizo Springs was by far the largest town in the county; in 1982 it had a population of 6,886 and 148 businesses. In 1984 Carrizo Springs was home to the county's only newspaper, the Carrizo Springs Javelin, and its only radio station. In 1988 the town reported 7,553 residents and 109 businesses. In 1990 the population was 5,745, and in 2000 it was 5,655.