On March 16, 1774, Juan Bautista de Anza, Indian fighter, explorer, and colonizer, led the first white explorers to cross the mountains into California through this pass, which he named San Carlos, as they traveled from Tubac, Arizona, to Monterey, California. On December 27, 1775, during a second expedition into California, Anza led through this pass a party of Spaniards from Sonora who became the founders of San Francisco.