The grant was located on the route of
El Camino Viejo. 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, and the grant was
patented to Guillermo Castro in 1865. Soon after, Castro began to sell off his land to pay debts. The last of his holding was sold in a sheriff's sale in 1864 to
Faxon Atherton. Atherton in turn began selling off his portion in smaller parcels. ==Rancho San Lorenzo (Sota)==