Rancho San Pablo was a 17939 acres (72.6 km²) land grant

Ranchos of California

The Spanish, and later the Méxican government encouraged settlement of territory now known as California by the establishment of large land grants called ranchos, from which the English ranch is derived. Devoted to raising cattle and sheep, the owners of the ranchos attempted to pattern themselves...

 in present day Contra Costa County, California

Contra Costa County, California

Contra Costa County is a primarily suburban county in the San Francisco Bay Area of the U.S. state of California. As of the 2010 census, it had a population of 1,049,025...

 given in 1823 by Governor Luís Antonio Argüello

Luis Antonio Argüello

Luis Antonio Argüello was the first native governor of Alta California from 1822 to 1825, during the period California was under Mexican rule, twelfth overall. He was the only governor to serve under the Mexican empire, and the first native Californian to hold that office...

 to Francisco María Castro

Francisco María Castro

Francisco María Castro was a landowner in an area of Alta California which later became part of Contra Costa County, California.Francisco María Castro was the third son of Joaquin Ysidro de Castro, one of the founding settlers of the Pueblo of San José and Maria Marina Botiller...

 (1775 - 1831), a former soldier at the San Francisco Presidio and one-time alcalde of the Pueblo of San José

San Jose, California

San Jose is the third-largest city in California, the tenth-largest in the U.S., and the county seat of Santa Clara County which is located at the southern end of San Francisco Bay...

. The grant was reconfirmed by Governor José Figueroa

José Figueroa

General José Figueroa , was a General and the Mexican territorial Governor of Alta California from 1833 to 1835.Figueroa oversaw the initial secularization of the missions of upper California, which included the expulsion of the Spanish Franciscan mission officials.This also involved the issuing of...

 in 1834 to the heirs of Francisco Castro, including Víctor Castro

Víctor Castro

Víctor Ramón Castro was a landowner in an area of Alta California which later became part of Contra Costa County, California.Víctor Castro was the son of Francisco María Castro, a former soldier at the San Francisco Presidio, one-time alcalde of the Pueblo of San José, and grantee of Rancho San...

. The San Pablo grant covered what is now Richmond

Richmond, California

Richmond is a city in western Contra Costa County, California, United States. The city was incorporated on August 7, 1905. It is located in the East Bay, part of the San Francisco Bay Area. It is a residential inner suburb of San Francisco, as well as the site of heavy industry, which has been...

, San Pablo

San Pablo, California

San Pablo is a city in Contra Costa County, California, United States. The city of Richmond surrounds nearly the whole city. The population was 29,139 at the 2010 census. The current Mayor is Paul V. Morris, and the current Vice Mayor is Cecilia Valdez. Current Councilmembers include Arturo M....

, and Kensington

Kensington, California

Kensington is an unincorporated community and census-designated place located in the East Bay, part of the San Francisco Bay Area, in Contra Costa County, California, United States. The population was 5,077 at the 2010 census.- Law and government :Kensington is an unincorporated area of Contra...

 in western Contra Costa County.

History

The land had previously been grazing land for cattle belonging to the Misión Dolores, but was secularized by the new Mexican republic. Francisco Maria Castro lived there with his wife María Gabriela Berreyesa

María Gabriela Berreyesa Castro

María Gabriela Berrelleza was born November 26, 1780, and christened the same day at Mission Santa Clara de Asís in upper Las Californias, near present day San José . She was the first child of the family of María Gertrudis Peralta and Nicholas Antonio Berrelleza...

 and family from the late 1820s until his death in 1831. Governor of Mexican Alta California

Alta California

Alta California was a province and territory in the Viceroyalty of New Spain and later a territory and department in independent Mexico. The territory was created in 1769 out of the northern part of the former province of Las Californias, and consisted of the modern American states of California,...

, Juan Alvarado, married one of the Castro daughters in 1839. After his term as governor was completed, they retired to her family property on Rancho San Pablo.

With the cession

Mexican Cession

The Mexican Cession of 1848 is a historical name in the United States for the region of the present day southwestern United States that Mexico ceded to the U.S...

 of California to the United States following the Mexican-American War, the 1848 Treaty of Guadalupe Hidalgo

Treaty of Guadalupe Hidalgo

The Treaty of Guadalupe Hidalgo is the peace treaty, largely dictated by the United States to the interim government of a militarily occupied Mexico City, that ended the Mexican-American War on February 2, 1848...

 provided that the land grants would be honored. As required by the Land Act of 1851, a claim claim for Rancho San Pablo was filed with the Public Land Commission

Public Land Commission

The Public Land Commission, a former agency of the United States government, was created following the admission of California as a state in 1850 . The Commission's purpose was to determine the validity of prior Spanish and Mexican land grants in California.California Senator William M...

 by Joaquín Ysidro Castro in 1852, and the grant was patented

Land patent

A land patent is a land grant made patent by the sovereign lord over the land in question. To make a such a grant “patent”, such a sovereign lord must document the land grant, securely sign and seal the document and openly publish the same to the public for all to see...

to Joaquín Ysidro Castro in 1878.