Moosehorn is one of the northern most national wildlife refuges in the Atlantic Flyway, a migratory route that follows the eastern coast of North America. The refuge provides important feeding and nesting habitat for many bird species, including waterfowl. Wading birds, shorebirds, upland game birds, songbirds, and birds of prey.

The refuge consists of two divisions. The Baring Division covers 20,016 acres and is located off U.S. Route 1, southwest of Calais. The 8,735 acre Edmunds Division is between Dennysville and Whiting on U.S. Route 1 and borders the tidal waters of Cobscook Bay. Each division contains a National Wilderness Area, thousands of acres managed to preserve their wild character for future generation.

The refuge's landscape is varied, with rolling hills, large ledge outcrops, streams, lakes, bogs, and marshes. A northern hardwood forest of aspen, maple, birch, spruce and fir dominates the upland. Scattered stands of majestic white pine are common. The Edmunds Division boasts several miles of rocky shoreline where tidal fluctuations of up to 24 feet occur twice a day.

Located in Washington County, it is here that Americans first greet the morning sun, and local citizens are proud of its nickname "Sunrise County". It was also here, in 1604, that the explorers Sieur DeMonts and Champlain celebrated the first Christmas in the New World.