Rancho Monte del Diablo was a 17,921-acre (72.52 km2) Mexican land grant in present-day Contra Costa County, California given in 1834 by Governor José Figueroa to Salvio Pacheco. The name "Monte del Diablo" means "thicket of the devil" in Spanish. The name was later incorrectly translated as Mount Diablo. The grant covered the area from the Walnut Creek channel east to the hills, and generally from the Mount Diablo foothills north along Lime Ridge to Avon on the Carquinez Strait of the Sacramento River, and included present day Concord and parts of Pleasant Hill. Pacheco and Clayton are outside of the Rancho Monte del Diablo grant.