Trigo Mountains Wilderness is a wilderness area in the U.S. state of Arizona and was established in 1990. It is located north of Yuma east of the Colorado River in an area called the Lower Colorado River Valley. It is a stretch of ridgeline of the rugged desert Trigo Mountains and is adjacent to historical mines, the Red Cloud and Hart Mine. These rugged desert mountain ecosystems are home to the Desert Bighorn Sheep.