Nabesna Glacier is a glacier in the U.S. state of Alaska. Fed by deep snowfall in the Wrangell Mountains, the 53 mile (85 km) long Nabesna is the longest valley glacier in North America and the world's longest interior valley glacier.The glacier flows from an extensive icefield which covers the northern flanks of 14,163 feet (4,317 m) Mount Wrangell, a large shield volcano.