Rancho San Lorenzo (Castro)

Rancho San Lorenzo was a 26,722-acre (108.14 km2) Mexican land grant given in 1841 by Governor Juan Alvarado to Guillermo Castro a career soldier posted to the Pueblo of San José.

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 San Lorenzo was filed with the Public Land Commission in 1852,[1][2] and the grant was patented to Guillermo Castro in 1865.

Atherton in turn began selling off his portion in smaller parcels.

[4] Guillermo and Maria Louisa Peralta Castro owned Rancho San Lorenzo Alta.

plaque outside the original Hayward City Hall building, at Alex Giualini Plaza