San Antonio, City (pop., 2020: 1,434,625), south-central Texas, U.S. It is situated at the headwaters of the San Antonio River. Founded in 1718 by the Spanish as the Mission San Antonio de Valero on the site of a Coahuiltecan Indian village, it was laid out as a town in 1731. The mission, later called the Alamo, became a military post in 1794; it was the site of a historic siege in 1836. In the late 19th century, as the starting point of the Chisholm Trail, the town became a major cattle centre. Military installations, especially for aviation and aerospace, spurred the city’s rapid growth after 1940. The economy is now diversified; government, business, manufacturing, education, and tourism are all important aspects of San Antonio’s growth. The Alamo and several other 18th-century Spanish missions near the city were collectively designated a UNESCO World Heritage site in 2015.
