In 1843, the Mexican government made grants for the land that became three ranches: the 26,626-acre (107.75 km2) Rancho Los Alamos y Agua Caliente; the 97,617-acre (395.04 km2) Rancho El Tejon; and the 22,178-acre (89.75 km2) Rancho Castac. A fourth tract, the 48,800-acre (197 km2) Rancho La Liebre, was granted in 1846.
At the urging of Edward Beale, Superintendent of Indian Affairs in California, the Sebastian Indian Reservation was established in 1853 on Rancho El Tejon, and Fort Tejon was established by the U.S. Army in 1854 on Rancho Castac. These were federal projects, consisting of major developments and improvements, on what was the Mexican grantees' private land.
In 1855, Edward Beale purchased Rancho La Liebre. The Army abandoned Fort Tejon in 1864. Beale bought Rancho El Tejon and Rancho de los Alamos y Agua Caliente in 1865, and Rancho Castac in 1866. With the purchase of these four Mexican land grants, Beale created the present day Tejon Ranch.
Beale's son, Truxtun Beale, sold the Tejon Ranch in 1912 to a syndicate of investors headed by Los Angeles Times publisher Harry Chandler and land developer Moses Sherman. Both had extensive holdings in the San Fernando Valley.
In 1936, the Tejon Ranch Company became a public company, with the Chandler–Sherman group retaining a controlling interest.
 Tejon Ranch Company
Tejon Ranch is the largest private landholding in California, and today is owned by Tejon Ranch Company, a company listed on the New York Stock Exchange.
Its principal activity is land development and agribusiness, increasing the value of real estate and resource holding on this land. The company operates in four segments of the economy:
 Future of the ranch
 Conservation and land-use agreement
A large number of California native plants occur on as yet undisturbed land owned by Tejon Ranch. It is situated at a section of the state where several ecoregions meet and overlap: the Mojave Desert, the Central Valley, the Sierra Nevada, and the Transverse Ranges of Southern California. The interaction of unique geography and varying climates has produced high biodiversity, as evidenced by showy spring wildflower blooms.Overlooking the eastern half of Tejon Ranch from the Tehachapi Crest. Frazier Mountain in the Los Padres National Forest is in the background.
An agreement between the Tejon Ranch Company and a coalition of environmental groups, announced in May 2008, is designed to permanently protect 240,000 acres of the historic ranch. It is the largest conservation and land-use pact in California history.
The agreement was finally reached to conclude 20 months of off-and-on negotiations, but only after a marathon three-day bargaining session in April 2008. California Governor Arnold Schwarzenegger traveled to the ranch in May of that year to take part in the announcement, but the signing of the agreement was done in private in June.