 After crossing the Colorado to avoid the impassable Algodones Dunes west of Yuma, Arizona, they followed the river about south (to about the Arizona's southwest corner on the Colorado River) before turning northwest to about today's Mexicali, Mexico and then turning north through today's Imperial Valley and then northwest again before reaching Mission San Gabriel Arcángel near the future city of Los Angeles, California.It took Anza about 74 days to do this initial reconnaissance trip to establish a land route into California.On his return trip he went down the Gila River until hitting the Santa Cruz River (Arizona) and continuing on to Tubac.