Anza, Juan Bautista de (1735–1788?), a Spanish explorer and founder of San Francisco. In 1774, while captain of a presidio (military post) in Pimería Alta (now Arizona), Anza opened an overland supply trail from Mexico to the Spanish missions at San Gabriel and Monterey in California. The following year, under instructions from the viceroy of New Spain, Anza led an expedition of 240 persons to San Francisco Bay. He explored the region, selecting the site where a presidio was founded by one of his lieutenants in 1776. Anza was governor of New Mexico, 1777–88.