On August 30, 1869, Major John Wesley Powell landed at the mouth of the Virgin River, about twelve miles south of here, thus ending the first expedition through the Grand Canyon of the Colorado River
The expedition left Green River City, Wyoming Territory, on May 24, 1869. For three months Powell and his men endured danger and hunger to explore, survey, and study the geology of the canyons along the Green and Colorado Rivers
Exhausted and near starvation, the Powell party was fed by the Mormons of St. Thomas, a small farm settlement about eleven 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, and later Powell surveys, stimulated interest in the water conservation problems of the Southwest.