Rancho El Sobrante
Rancho El Sobrante was a 20,565-acre (83.22 km2) Mexican land grant in present-day Contra Costa County, California given in 1841 by Governor Juan Alvarado to Juan Jose Castro and Victor Castro. The name means "left over " in Spanish—the grant's boundaries were determined by the boundaries of the surrounding grants: San Antonio, San Pablo, El Pinole, La Boca de la Cañada del Pinole, Acalanes, and La Laguna de los Palos Colorados. This grant included the area between present day El Sobrante and Orinda.
Brothers Juan Jose Castro (1803–1869) and Victor Ramon Castro (1817–1897) were among the eleven children of Francisco María Castro (1775–1831) and María Gabriela Berreyesa (1780–1851). Francisco Castro had been a soldier at San Francisco, who after serving as alcalde and in other public offices, was granted Rancho San Pablo in 1823. Juan Castro and Victor Castro served in the San Francisco militia.
Juan Alvarado, married María Martina Castro (1814–1875) in 1839, and was thus brother-in-law to Juan Jose Castro and Victor Castro. Juan Castro was grantee of Yerba Buena Island in 1838, and Victor Castro was grantee of Mare Island in 1841. But neither brother settled permanently, and both grants were rejected by the Public Land Commission. Juan Castro and Victor Castro then identified an area of land which was not described in any land grants of the time, and applied for a grant for Rancho El Sobrante.
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