Located in southeast Arkansas in Ashley County, Overflow National Wildlife Refuge was established in 1980 to protect one of the remaining bottomland hardwood forests considered vital for maintaining mallard, wood duck, and other waterfowl populations in the Mississippi Flyway. This 13,000 acre plus wetland complex consists of seasonally flooded bottomland hardwood forests, impoundments, and croplands. During the winter, a 4,000 acre greentree reservoir is created when the bottomland hardwood forests are allowed to flood. This seasonally flooded area provides a haven for mallards, wood ducks, and other waterfowl species. This refuge is a wetland complex within the watershed of Overflow Creek which flows southerly along the length of the refuge. On the west boundary, there are only about 100 acres of uplands found on a narrow strip along the escarpment that separates the Mississippi Delta from the Coastal Plain. The majority of the refuge is bottomland hardwood forest consisting primarily of willow and overcup oaks. Willow oaks, found here in abundance, produce small acrons that are an excellent source of food for the mallards and wood ducks that make their winter home here. Throughout the refuge are a number of impoundments, where the water and the plants are managed to benefit wildlife living on the refuge, especially waterfowl. These areas, called moist soil units, are very important in excuring that there is enough food for the birds that spend the winter here. Natural foods provide essential nutrients for birds to survive the winter and nest successfully in the spring. These moist soil units, along with the croplands, and bottomland hardwoods forest provide a mix of habitats that support a variety of wildlife throughout the year.

Overflow Refuge headquarters is located off of Arkansas Highway 8 approximately 15 miles east of Hamburg and 5 miles west of Parkdale .