Cranesville Swamp is located in Preston County, West Virginia, and Garrett County, Maryland. The swamp totals nearly more than 1,600 acres. A high mountain bog formed thousands of years ago, the swamp is a unique ecological area. Many plants and animals common to more boreal and northern areas such as Canada, live at Cranesville as survivors from the Ice Age. Special physiographic conditions at the swamp help maintain these relict populations.

The area, named for local "cranes" (actually blue herons), was described by the mountain man and hunter Meshach Browning, who stated that the swamp area in the 1850s was full of panthers, wolves, bobcats, black bears, trout, and other wildlife. Today, the Nature Conservancy owns Cranesville Swamp. Visitors to the sanctuary may tour the swamp by a boardwalk leading into the bog. There they can see eastern larch, a northern deciduous swamp conifer, and other bog plants including cottongrass, cranberry, and the carnivorous sundew. The swamp was named a National Natural Landmark in 1964.