Fed by deep snowfall in the Wrangell Mountains, the 53 mile (85 km) long [1] Nabesna is the longest valley glacier in North America[2] and the world's longest interior valley glacier.

[3] 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.

It heads initially east past other volcanic peaks including Mount Blackburn and Atna Peaks and then turns north to its terminus near 3,000 ft (900 m) elevation, about 15 mi (24 km) south of the old mining settlement of Nabesna at the end of the Nabesna Road.

Ski-equipped bush planes can typically land between 6,000 and 7,000 ft (1,800-2,100 m) on the central portion of the glacier when the ice and crevasses are covered by winter snow.

There is evidence to indicate that this retreat may have been going on even longer than that, as glacial deposits much farther down the valley indicate that it may have once been over 200 miles long.