The first use of the name "Rio San Juan" (after San Juan Bautista, the Spanish name for Saint John the Baptist) was apparently by Spanish explorer Juan Rivera, who led an expedition to the area in 1765. Rivera's route would later become part of the Old Spanish Trail between Santa Fe, New Mexico and Southern California. About a decade later in 1776, the Domínguez–Escalante expedition passed through the San Juan River country, attempting to find a route from Santa Fe to the presidio in Monterey, California. Domínguez and Escalante crossed the San Juan River near where Navajo Lake is today, and described the area as having good land suitable for settlement and farming, but also "excessively cold even in the months of July and August." The expedition was unsuccessful, turning back at Utah Valley, but their discoveries were crucial in opening up the region to future European settlement.