Prehistorically, the San Dieguito tribe inhabited much of San Diego County, with their main villages on the San Dieguito River. Remains of this culture are identified as the "San Dieguito River Complex". By the 16th century, most of the basin formed the southern part of the
Luiseño tribal territory. The
Portola expedition of 1769 camped at the river, not far from the coast. On the
De Anza Expedition's way back to Mexico from
San Francisco Bay, Father Pedro Font mentions "San Dieguillo" in his diary on January 10, 1776. An Indian rancheria, San Dieguito, is mentioned under the jurisdiction of the San Diego Mission in 1778. In 1840 or 1841, after the
Mission Period, the name was applied to the
Rancho San Dieguito, which was granted in 1845. The rancho name was later changed to
Rancho Santa Fe. ==Crossings==