The Imperial National Wildlife Refuge Wilderness is split between Arizona and California with 9,220 acres in Arizona. This Wilderness is strung out along the Colorado River, upstream of the Imperial Dam. The dam caused the formation of many backwater lakes of all different sizes: from about 700 acres to as small as 1/2 acre. The Imperial National Wildlife Refuge was established here in 1941 and the Wilderness was officialy designated in 1994.

The Colorado River in this area has plenty of largemouth and striped bass but you'll have to do your fishing from a boat: the Imperial National Wildlife Refuge Wilderness is completely closed to public access. The nearest camping is at Picacho State Park on the California side of the river.