Rioville and Saint Thomas before Hoover Dam:
Historical Topographic Map Collection Courtesy of USGS
Lake Mead After Hoover Dam:
Rioville and Saint Thomas in the 1890 to 1920 Mining Boom:
Hand drawn map by Stowell E. Whitney based on his own recollections. In the years prior to World War One, Whitney used teams of draft horses to pull wagon loads of copper, gold, and silver ore from the Grand Gulch Mine to the railhead at Saint Thomas. The ore was weighed and graded at the Gentry Store Assay Office and then loaded on rail cars. Following the war, the price of copper dropped drastically due to increased international competition and the Grand Gulch went out of production.