Guam National Wildlife Refuge is located on the island of Guam, an unincorporated U.S. Territory. Guam is the largest and southernmost island in the Mariana Archipelago, situated in the western Pacific Ocean, approximately 3,700 miles west of Honolulu and 1,500 miles south of Tokyo. The Guam NWR is comprised of three units: the Andersen Air Force Base Overlay Refuge Unit, the Navy Overlay Refuge Unit, and the Ritidian Unit. The Ritidian Unit is located on the northern tip of Guam and encompasses approximately 1,203 acres, including 400 terrestrial acres and 832 acres of submerged offshore area.