Rancho Suscol was a 84,000-acre (340 km²) Mexican land grant in present day Napa County, California and Solano County, California given in 1843 by governor Manuel Micheltorena to General Mariano Guadalupe Vallejo. In a significant land law decision, the land claim was rejected by the US Supreme Court in 1862. Rancho Suscol extended from Rancho Petaluma on the west, south down to the San Francisco Bay and Mare Island and Carquinez Strait, and then to Rancho Suisun on the east.