Course of the Colorado River Davis Dam in Pyramid Canyon above Laughlin, Nevada, where a bridge carries NV 163 (Laughlin Highway)/AZ 95 over the Colorado River. Prior to the completion of the Hoover Dam Bypass project in 2010, this bridge was the main crossing for freight traffic between Arizona and Nevada as trucks were not allowed over Hoover Dam for security reasons after the September 11, 2001 attacks. The Colorado then passes by Bullhead City, Arizona and Fort Mohave, Arizona and the Fort Mojave Reservation. The Colorado forms the border of California to the west and Arizona to the east for most of its course
Black Canyon of the Gunnison National Park into Gunnison Gorge National Conservation Area. The canyon's name owes itself to the fact that parts of the gorge only receive 33 minutes of sunlight a day, according to "Images of America: The Black Canyon of the Gunnison". In the book, author Duane Vandenbusche states, "Several canyons of the American West are longer and some are deeper, but none combines the depth, sheerness, narrowness, darkness, and dread of the Black Canyon." The Gunnison River drops an average of through the entire canyon, making it the 5th steepest mountain descent in North America. By comparison, the Colorado River drops an average