Juan Bautista De Anza led two groups of Spanish explorers and settlers across this portion of the Colorado Desert from Northern Mexico to San Francisco Bay, and during each difficult passage the Spanish camped below here in Yuha Wash. The 1774 passage, which explored and pioneered the first overland route into upper California, included only a small group of soldiers and two missionaries, Father Garces and Diaz. A second trip in 1775 brought settlers to the coast of California. Spain believed its tenuous hold on the New World was threatened by Russian settlements to the north, and the Spanish missions were struggling to survive and needed a reliable supply route to ensure military, political, and religious success. This expedition included 240 people, among them Captain De Anza, 38 soldiers, 15 muleteers, 136 colonists, several Indian guides, and Father Pedro Font as chronicler, along with more than 800 head of livestock including pack mules, horses, and cattle. The settlers became founders of what would become San Francisco. The route discovered by De Anza was abandoned in the 1780s because of Quechan Indian hostilities, but portions were used during the 1800s as part of the Gila and Overland Trails and later by gold seekers and several stage lines.