Rancho Todos Santos y San Antonio was a 20,772-acre (84.06 km2) Mexican land grant in present-day Santa Barbara County, California given in 1841 by Governor Juan B. Alvarado to William Edward Petty Hartnell.
[1] The grant extended along San Antonio Creek and encompassed present-day Orcutt., northwest of Lompoc[2][3] W. E. P. Hartnell (1798–1854) received the five square league Rancho Todos Santos y San Antonio grant from Alvarado in appreciation of Hartnell’s service as Inspector General of Missions (visitador de misiones) after the secularization of the Missions.
In 1844, Hartnell also obtained the eleven square league Rancho Cosumnes from Governor Manuel Micheltorena.
With the cession of California to the United States following the Mexican-American War, the 1848 Treaty of Guadalupe Hidalgo provided that the land grants would be honored.
Hartnell wrote in his will - "My principal object is to prevent any member of the law from having anything whatsover to do with my property or with my executors or heirs."