San Elizario (San Elceario, San Elzeario) is at the intersection of Farm roads 258 and 1110, fifteen miles southeast of downtown El Paso in southern El Paso County. Juan de Oñate reached the Rio Grande at or near the site of present San Elizario on April 20, 1598, and ten days later took formal possession of New Mexico and all adjacent territory in the name of the Spanish king. A settlement known as the Hacienda de los Tiburcios was founded at the site, then south of the Rio Grande, sometime before 1760 and had a population of 157 in 1765. In 1789 the Spanish presidio, located in the Valle de San Elizario opposite Fort Hancock, was moved to the Hacienda de los Tiburcios; the presidio kept its old name, however, and the settlement that grew up around it became known as San Elizario.
San Elizario was second only to El Paso del Norte among local towns for most of the nineteenth century. Merchant caravans passed through the town before the opening of the Santa Fe Trail, and Zebulon M. Pike and Peter Ellis Bean, a survivor of the Nolan expedition, were held there in 1807. In 1821, after the Mexican War of Independence from Spain, San Elizario became part of the state of Chihuahua. Mexican troops still occupied the old presidio in 1835, and it served as a nucleus for a town which by 1841 had a population of 1,018. In 1830–31 the unpredictable Rio Grande changed course, placing San Elizario and its neighboring communities on La Isla, between the old and new channels of the river. Members of the Doniphan expedition occupied the presidio in February 1847, and one year later, when the Treaty of Guadalupe Hidalgo established "the deepest channel" of the Rio Grande as the boundary between Texas and Mexico, San Elizario became part of Texas. The town lay on the Lower El Paso or Military Road from Corpus Christi to California, and hundreds of Forty-Niners passed through in the late 1840s. Many visitors admiringly described the local peaches, plums, and wheat, and the wine produced from San Elizario grapes was held in high regard. Companies of the Third Infantry under Jefferson Van Horne were stationed there from 1849 to 1852, and in 1850, when El Paso County was officially organized, San Elizario was selected the county seat. Except for brief periods in 1854 and 1866, it remained the county seat until 1873. A post office was open in San Elizario from 1851 to 1869. During the Civil War troops of the California Column occupied the old presidio, but after the war it was finally abandoned for good.
After 1873 San Elizario began to decline in importance. Perhaps the most notorious episode in the history of the town was the 1877 Salt War of San Elizario, in which several men died in a dispute over rights to the salt deposits just west of the Guadalupe Mountains, ninety miles to the east. After the salt war many residents of San Elizario fled across the Rio Grande to escape punishment, and in 1881 the town was bypassed by the railroad in favor of El Paso. In 1890 the estimated population was 1,500, and the town had two schools and a steam flour mill. In 1904 it still had an estimated population of 1,426, but ten years later that figure had declined to 834. In 1931 the estimated population fell to 300, but it climbed to 925 by the mid-1940s and to 1,064 by the early 1960s. In 1990 it was 4,385. The population more than doubled reaching 11,046 in 2000.