The Spanish explorer Juan Bautista de Anza (1735-1788) opened the overland route from Mexico to California and established the first settlement at San Francisco.

Juan Bautista de Anza was born in Fronteras, Sonora, Mexico, where his grandfather and father had served as commanders. In 1738 Anza's father submitted a plan for opening a route from Sonora to California, but in 1739 the elder Anza lost his life in a campaign against the Apaches and the plan was dropped.

When Anza was 18 he volunteered for military service and rapidly rose to the rank of captain. In 1759 he became commander of the presidio of Tubac (south of modern Tucson). He led numerous campaigns against the Apaches and achieved a notable reputation as a soldier and leader.

By 1770 the Spanish settlements in California were in desperate condition. Routes by sea and over the peninsula of Baja California could not supply their needs, and there was great fear that California would have to be abandoned. Remembering his father's ambitions, Anza volunteered to open a route from Sonora, and in 1773 Viceroy Antonio Maria de Bucareli granted him permission to attempt the journey. Setting out in January 1774 with 34 men, including the Franciscan Fray Francisco Garcés, Anza traveled to the Colorado River, where he established friendly relations with the Yuma Indians. Turning westward, he broke a trail across the southern desert to San Gabriel in Alta (upper) California.

Bucareli promoted Anza to lieutenant colonel and placed him in charge of recruiting colonists for a new California settlement. In 1775 he left Mexico with 240 colonists, including women and children. In March 1776 the group reached California with the loss of only one life, an almost unheard-of feat in those times.

Anza selected the site for the pueblo of San Francisco and then returned to Mexico, where Bucareli named him governor of New Mexico. Anza proved an excellent governor. His campaigns against the Apaches and Comanches brought peace to the northern frontier, and his reorganization of the defenses of the province strengthened Spanish domination in the area.

In 1781 the Yuma rose against the Spaniards, and Anza, who was unfairly blamed for the revolt, lost his post. However, he soon returned to office and served until 1786, when he requested transfer to a more healthful climate. He went to Tucson as commander and served there until his death in Arizpe in 1788.