The San Antonio Conservation Society was organized on March 22, 1924, under the leadership of Emily Edwards and Rena Maverick Green. San Antonio was the largest city in Texas at that time, and its rapid growth was threatening many of the historic aspects of the city. The ladies were particularly concerned with a street-widening project that threatened the distinctive old Market House, built in 1859 and one of the city’s few examples of Greek Revival architecture. The thirteen women present at the organizational meeting vowed not only to seek preservation of the Market House but also “to co-operate in the preservation of the Missions, to conserve Old Buildings, Documents, Pictures, Names, Natural Beauty and anything admirably distinctive of San Antonio”—in a phrase, “cultural conservation.” Although Market Street was widened and the Market House was taken down, the city promised to preserve its façade for use in construction of the 700-seat San Pedro Playhouse, to be the home of the San Antonio Little Theater in San Pedro Park. The stonework was found, however, to have been so roughly dismantled that it could not be reused. When the Playhouse opened in 1930, the city sought to placate society members by having the façade, in new stone, replicate that of the old Market House.
By then the Conservation Society had been maintaining an active interest in helping establish the Witte Museum, backing restoration of the Spanish Governor's Palace, supporting state purchase of land behind the Alamo, encouraging preservation of trees along the San Antonio River, maintaining original street names, and lobbying the city to establish a municipal planning department. But its greatest energies were directed toward the restoration and preservation of San José Mission in its “naturally beautiful setting.” The society became among the first preservation groups in the nation to advocate preservation of not just an individual landmark but its entire historic natural environment as well, as Britain’s National Trust for Places of Historic Interest or Natural Beauty had been doing since the 1890s. The San Antonio Conservation Society incorporated in 1925 so it could legally hold property and quickly began purchasing the small individual tracts that once made up the original mission compound and its grand plaza. Society leaders inspired local and federal funding to help restore the mission’s vaulting granary and helped in restoration of the mission church and the compound’s exterior walls. The society’s goal of incorporating San José in a national historical park was not realized until 1983 (see San Antonio Missions National Historical Park), but in the meantime—in mid-1941—the society was instrumental in encouraging the city, the county, and the Catholic Church to join with the society in turning over their combined San José Mission properties to the state of Texas for management as a state park.
In 1941 the society purchased property that contained the 200-year-old aqueduct that carried water to San Francisco de la Espada Mission, designated a national historic landmark in 1966. This site was also transferred to the National Park Service for inclusion in the San Antonio Missions National Historical Park which began operations in 1983. In 1942 the 1850 Jeremiah Dashiell House, an old stone house overlooking the river bend, was purchased and became the society's headquarters; in 1950 the nearby 1855 Otto Bombach House was acquired. In 1957 twenty-five acres of pecan bottomland near the acequia of San Juan Capistrano Mission was acquired, and Acequia Park was established, deeded to the city of San Antonio in 1975, and transferred to the National Park Service in 1983. Scheduled for demolition in 1960, a group of three stone buildings that had been the home of José Antonio Navarro was acquired and restored. In 1975 this property was deeded to the Texas Parks and Wildlife Department, which maintained it as the José Antonio Navarro State Historical Park until 2008 when it was transferred to the Texas Historical Commission and was known as the Casa Navarro State Historic Site. In 1961 the society was given the Yturri-Edmonds home and the Travieso Mill on Old Mission Road. The Oge Carriage House from King William Street and the 1855 Postert House, a small caliche block and stone rubble structure, were moved onto this property. This historic site currently serves as a house museum operated by the society. In 1965 sections of the Ursuline Convent (see URSULINE ACADEMY, SAN ANTONIO), designed by early architects Jules Poinsard and François P. Giraud, were purchased, and in 1969 this property was entered in the National Register of Historic Places. In 1975 the society sold this property to the Southwest Craft Center, which operates a creative arts and crafts school at the site. Three outstanding houses, the 1876 Steves Homestead, the 1876 Ike West Home (both on King William Street in the King William Historic District), and the Charles Zilker House on Elm Street, were acquired. Other sites and structures acquired by the society between 1952 and 1988 for purposes of preservation include the O. Henry House, the 1870 Anton Wulff House, the 1870 Louis Gresser House, the 1893 Staacke Building, the 1891 Stevens Building, the 1913 Rand Building, the 1878 Hertzberg Clock, the 1867 August Stuemke Barn, and the 1926 Aztec Theatre. In every case the society assumed ownership of historic properties only to protect, preserve, or restore them, and then found an appropriate use for each. Some have been sold or given to other organizations and individuals, while a few are still owned by the society. The Steves Homestead, for example, has been maintained by the society as a historic house museum since 1954, while the Anton Wulff House has served as society headquarters since 1975. In addition, the society accepts façade easements as a means of ensuring the preservation of historic structures. The society currently holds five façade easements-for the 1891 Reuter Building, the 1879 Old Bexar County Jail, the 1926 Emily Morgan Hotel, the 1906 Fairmount Hotel, and the 1925 Builders Exchange Building.
The society achieved national recognition for its long-standing annual Christmas presentations of two Mexican folk dramas, Los Pastores ("The Shepherds") and Las Posadas ("The Inns"). Also popular since its inception in 1947 is Night in Old San Antonio, held each spring at the time of Fiesta San Antonio in La Villita. Ecology was also an interest of the group. San Pedro Park was preserved as a recreational area through the society's efforts in the late 1940s; an annual tree-selling project was sponsored beginning in 1952, and trees were planted as well as sold by the organization. Travis Park, which had been deeded to the city in the 1850s, was leased by the city in 1954 to a corporation for an underground parking garage. The Conservation Society brought suit, and in a state Supreme Court decision in 1957 the lease arrangement was declared null and void, thus proving the society's contention that dedicated parkland had legal rights; Travis Park was therefore preserved as a city parkland.
In 1947 the Conservation Society added an associate membership, from which new active members were taken, and in 1955 a junior associate membership was created to enable young members to study regional history and traditions. Beginning in 1949 the society annually presented awards to people and organizations that best served the cause of conservation. The society's charter was amended in 1962 to include members' concern for the state's natural beauty and to emphasize the educational character of the society. An adjunct to the organization, the San Antonio Conservation Society Foundation, was chartered by the state on May 19, 1970. In 1975 the Conservation Society relocated its headquarters to the restored Anton Wulff House at 107 King William Street, and in 1982 the August Stuemke Barn was moved to the site. The society has had more than forty-five presidents since its organization; Emily Edwards served as the first president from 1924 to 1926, and Susan Beavin served as president in 2018.