On August 30, 1869, Major John Wesley Powell landed at the mouth of the Virgin River, about 12 miles south of here, ending the first boat expedition through the Grand Canyon of the Colorado River. The expedition had left Green River City, Wyoming Territory, on May 24, 1869. For three months Powell and his men endured danger and hunger while exploring, surveying, and studying the geology of the canyons along the Green and Colorado Rivers. Exhausted and near starvation, the party was warmly greeted and fed by the Mormon pioneers of St. Thomas, a small farm settlement about 11 miles north of here. The original sites of St. Thomas and the junction of the Virgin and Colorado Rivers are now beneath the waters of Lake Mead. This expedition, and later Powell surveys, stimulated great interest in the water conservation problems of the Southwest.