Salt River Bay National Historic Park and Ecological Preserve is a unit of the National Park Service on the island of St. Croix in the U.S. Virgin Islands. It preserves upland watersheds mangrove forests and estuarine and marine environments that support threatened and endangered species. In 2010 the United States Mint began issuing 56 quarter-dollar coins featuring designs depicting national parks and other national sites as part of the United States Mint America the Beautiful Quarters Program.