Rancho San Leandro

Rancho San Leandro was a 6,830-acre (27.6 km2) Mexican land grant in present-day Alameda County, California, given in 1842 by Governor Juan Alvarado to José Joaquín Estudillo.

In 1823, Estudillo married Juana del Carmen Martinez (daughter of Ygnacio Martínez, grantee of Rancho El Pinole).

[5] With the cession of California to the United States following the Mexican-American War, the 1848 Treaty of Guadalupe Hidalgo provided that Mexican land grants would be honored.

The vaguely defined eastern boundary of the grant caused problems with his Rancho San Lorenzo neighbor Guillermo Castro.

[10][11][12] After the US Supreme Court ruled in favor of the Estudillo family, many of the squatters purchased the land.