Bill Williams River National Wildlife Refuge, Wildlife refuge in Mohave County, United States.

Bill Williams River National Wildlife Refuge protects the lower Bill Williams River to its mouth at Lake Havasu, in eastern La Paz and Mohave counties, Arizona. Its desert riparian corridor holds the largest remaining stand of Fremont's cottonwood and Goodding's willow along the lower Colorado River, with saguaro cactus, cattail marsh and open water in one view.

The Nature Conservancy acquired the land from the Arizona Ranch and Metals Company in 1977 and donated it to the U.S. Fish and Wildlife Service, which manages the refuge today. The protected area covers the lower Bill Williams River down to its mouth at Lake Havasu, within La Paz and Mohave counties.

The Friends of Bill Williams River organization supports the refuge through educational programs, fundraising activities, and maintenance assistance throughout the year.

You can enter the refuge from several access points and explore trails on foot, paddle down the river by kayak, or observe wildlife from designated viewing areas. The most comfortable season to visit is fall through spring when temperatures are moderate and outdoor activities are most enjoyable.

The refuge protects the largest remaining stand of cottonwood-willow forest along the lower Colorado River, with Fremont's cottonwood and Goodding's willow as the main trees. Its desert riparian habitat draws neotropical migratory birds from Central and South America and hosts the endangered southwestern willow flycatcher, which nests here.