Rancho Pauma was a 13,310-acre (53.9 km2) Mexican land grant in present-day Pauma Valley, in San Diego County, California, given in 1844 by Governor Manuel Micheltorena to José Antonio Serrano, Blas Aguilar, and José Antonio Aguilar.
[3] In 1838, José Serrano married Rafaela, daughter of Rosario E. Aguilar, majordomo of San Diego Mission.
[4] 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.
As required by the Land Act of 1851, a claim for Rancho Pauma was filed with the Public Land Commission in 1852,[5][6] and the grant was patented to José Antonio Serrano, Blas Aguilar and José Antonio Aguilar in 1871.
In 1892, the ranch site was designated as part of the Pauma and Yuima Reservation.