The 25,768-acre refuge protects 30 miles of wildlife habitat along the lower Colorado River. In 1938, Imperial Dam was completed on the river north of Yuma, Arizona. The waters stored behind the dam formed numerous backwaters and marsh areas along the edges of the river. These wetlands provided excellent resting, feeding, and nesting habitat for a variety of migratory birds and other wildlife. Serving as a boundary between Arizona and California, this portion of the river includes the last un-channelized section before its waters enter Mexico. The river and its associated backwater lakes and wetlands are a green oasis and a significant contrast with the surrounding desert mountains.
Imperial National Wildlife Refuge was established to protect these wetland habitats. It includes more than 15,000 acres of federally designated wilderness and is part of the National Wildlife Refuge System, a national network of lands and waters set aside for the benefit of wildlife, habitat and you.