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
Course of the Colorado River flows through the Parker Valley, much of which belongs to the Colorado River Indian Reservation, and then the Palo Verde Valley, where it is crossed by Interstate 10 near Blythe, California. The small Headgate Rock Dam removes water for irrigation in the Parker Valley and the Palo Verde Dam provides water to the Palo Verde Valley. The river then flows through a canyon in the Trigo Mountains, where the Cibola and Imperial National Wildlife Refuge encompass the wetland areas formed above Imperial Dam, which filled with silt shortly upon its completion in the 1930s. Most of the Colorado's remaining flow