Clarence Cannon National Wildlife Refuge is a three thousand seven hundred fifty-acre refuge in Pike County, Missouri, on the Mississippi River floodplain beside Pool No. 25. Its varied floodplain habitats support many kinds of birds, including waterfowl, wading birds, shorebirds, and songbirds. Even with levee protection, the refuge continues to help store floodwater during high water along the river. It is managed by Great River National Wildlife Refuge as part of the Mark Twain National Wildlife Refuge Complex.