Guillermo Castro (soldier)

Guillermo Castro
Portrait by Leonardo Barbieri; 1852.
Born	1809 Rancho San Francisco de las Llagas, San Martin, California
Died	1866
Occupations	Ranchero military officer surveyor
Spouse	Luisa Peralta

Don Guillermo Castro, born in 1809 in Spanish Alta California, was a Californio ranchero, military officer, local justice of the peace and surveyor who once owned vast land holdings in Alameda County. He is the namesake of the unincorporated community of Castro Valley, California and his land included most of the modern City of Hayward, California.