El Rancho Rinconada de los Gatos was a 6,631-acre (26.83 km2) Mexican land grant in present-day Santa Clara County, California made in 1840 by Governor Juan Alvarado to Jose Maria Hernandez and Sebastian Fabian Peralta. Located in the southern San Francisco Bay Area, the grant included present-day Los Gatos and Monte Sereno, along with about a third of Campbell. It also included small sections of present-day San Jose, Saratoga and unincorporated Santa Clara County.Los Gatos Creek flowed through the center of the rancho. The name means "corner of the cats" and is derived from the cougars that are still present in the nearby hills, as well as the "corner" formed by the narrowing gap between El Sereno and El Sombroso mountains.
Sebastian Peralta and José Hernandez, brothers-in-law married to two Sibrian sisters, were granted the one and one half square league Rancho Rinconada de Los Gatos in 1840. Sebastian Fabian Peralta (1794–?) married María Gregoria Sibrian (1806–1837) in 1831. After she died, he married María Paula Sepulveda, widow of Francisco Pacheco, in 1846. He was regidor of San José. José Maria Hernandez (1802–?) married Maria Gertrudis Sibrian (1810–1851) in 1830. After she died, he married Maria Espectacion Pena. They built an adobe home where Vasona Park is now.
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 Rinconada de Los Gatos was filed with the Public Land Commission in 1852, and the grant was patented to Sebastian Peralta and José Hernandez in 1860.