Fortification Rock
Former land feature on the Colorado River / From Wikipedia, the free encyclopedia
Fortification Rock, once a landmark hill on the Colorado River before it was inundated, now known as Rock Island,[1] southernmost and tallest of the Boulder Islands[2] in Lake Mead, Clark County, Nevada. It has an elevation of 1284 feet. Fortification Rock appears on the 1861 Geological Map No. 1; Rio Colorado of the West, explored by 1st Lieut. Joseph C. Ives, which shows Fortification Rock, Ives Camp #59 and the course of the Colorado River from its mouth on the Gulf of California to Las Vegas Wash and the location of its features and other expedition camps along the way.[3]