Sutter National Wildlife Refuge is a protected wetland in California’s Sacramento Valley, about 50 miles north of the Sacramento metropolitan area and the southernmost unit of the Sacramento National Wildlife Refuge Complex. Covering about 2,600 acres of wetland impoundments, riparian forest, and grassland, it is shaped by annual flooding within the Sutter Bypass, a floodwater channel linked to the Sacramento River. The refuge is especially significant for birds, supporting large winter populations of ducks and geese, breeding and migration habitat for passerines, and a major heron and egret rookery. It also shelters several federally and state listed species.