The Hoover Dam and Colorado River photographs depict the planning and construction of the Hoover (Boulder) Dam on the Colorado River from approximately 1925 to 1960. The photographs primarily depict the Colorado River, Black Canyon, construction machinery, the dam's diversion tunnels, and the completed dam. Much of the material is comprised of photographic postcards. The items described include black-and-white photographic prints, postcards, negatives, and slides; items listed are photographic prints unless otherwise specified.