The Olivas Adobe in Ventura, California is an adobe structure built in 1837 by Raymundo Olivas on the north bank of the Santa Clara River about a mile from the estuary where it flows into the Santa Barbara Channel. Olivas received, in recognition of his service at the Presidio of Santa Barbara, approximately 2,250 acres (9 km2) as part of land grant from Governor Juan Bautista Alvarado in 1841, which he named Rancho San Miguel. The land had originally been part of grazing area for the cattle herds of Mission San Buenaventura but was appropriated during the secularization of the missions lands.