Rancho El Pinole was a 17,761-acre (71.88 km2) Mexican land grant along Carquinez Strait in present-day Contra Costa County, California.
In 1834 Martinez appealed to Mexican authorities, saying that he had lost his title papers for a land grant made to him by Governor Luís Antonio Argüello in 1823 for his military service.
Martinez occupied and cultivated a large portion of the land, including setting up a vineyard and fruit orchards.
The Martinez descendants did so with the Public Land Commission in 1852,[5][6] and the grant was patented to María Antonia Martínez de Richardson et al. in 1868.
Later the heirs of William Welch of the adjacent Rancho Las Juntas, who owned the property on the east side of Arroyo del Hambre (Alhambra Creek), contributed another 500 acres (2.0 km2) to be included in the new town.