Alamo Heights, off U.S. Highway 281 five miles northeast of the center of San Antonio in north central Bexar County, has always been economically and socially a part of San Antonio. The area below the headwaters of the San Antonio River in Brackenridge Park in Alamo Heights was an Indian campground and haven for many explorers, travelers, and troops; visitors included Álvar Núñez Cabeza de Vaca, Domingo Terán de los Ríos, and Fray Damián Massanet. Massanet celebrated Mass at the spot in 1691 and changed the name from Yanaguana to San Antonio de Padua. In 1718, with the founding of San Antonio de Béxar, the use of the headwaters was guaranteed to the missionaries and early settlers under the rules of the Recapitulation of the Indies. In 1731 the Canary Islanders were granted similar rights to the use of the river.
In 1836 the land known as Alamo Heights was included as public land in the original survey of the city of San Antonio, but in December 1837 a city ordinance provided for sale of public lands at auction to provide funds for city improvements. Despite controversy over the proposed sale, the site of Alamo Heights was purchased by James R. Sweet. After several sales the property was bought by Mrs. Isabel Brackenridge in 1869. In 1897 her son, George W. Brackenridge, sold the family estate, Fernridge, and 200 acres of land containing the springs of the San Antonio River to the Sisters of Charity of the Incarnate Word. Incarnate Word College is on the boundary line between San Antonio and Alamo Heights, and Fernridge is preserved by the sisters as a museum building.
Alamo Heights was also the location of the "Arsenal Lot," donated by San Antonio to the federal government as an arsenal site in 1852 and returned to the donor in 1859. Charles Anderson bought the site in 1860, established a ranch, and built a home that subsequently became the Argyle Hotel. William McLane bought the property in 1861. Around 1890 his son, Hiram H. McLane, sold the area to a development company. Progress was slow until 1909, when Clifton George took over the company and began a program of expansion that included an adequate school building for the growing community.
In the early 1920s, as San Antonio expanded, the city developed annexation schemes to bring Alamo Heights into the city government; but, following two mass meetings, in 1922 Alamo Heights was voted an independent municipality. Voters also approved an independent school system. The 1926 completion of the Olmos Reservoir provided a further impetus to development in Alamo Heights.
Texas Military Institute was located in Alamo Heights from 1911 to 1989. Currently located in Alamo Heights are a public swimming pool, a post office, and a shopping center; the McNay Art Institute adjoins the municipality on the north. Adjacent to the Argyle Hotel is Cathedral House, headquarters of the Episcopal Diocese of West Texas, with conference center and chapel housed in the Spanish-style former Harry Halff residence and offices in a contemporary stone building. On Cathedral House grounds are the headwaters of the San Antonio River, described in diaries of Mary Adams Maverick in 1839 and a visiting Englishman, James Freemantle, in 1863. Newspapers that have been published in Alamo Heights include the Alamo Heights Herald in the 1920s and the Alamo Heights News, from 1939 to the early 1960s. The population in 1950 was 7,950, 7,552 in 1960, and 6,933 in 1970. In 2000 Alamo Heights had a reported 7,319 residents.