Mount Sanford is a shield volcano in the Wrangell Volcanic Field, in eastern Alaska near the Copper River. It is the third highest volcano in the United States behind Mount Bona and Mount Blackburn. The south face of the volcano, at the head of the Sanford Glacier, rises 8,000 ft in one mile (2,400 m in 1,600 m) resulting in one of the steepest gradients in North America.
Mount Sanford is mainly composed of andesite, and is an ancient peak, being mostly of Pleistocene age, although some of the upper parts of the mountain may be of Holocene age. The mountain first began developing 900,000 years ago, when it began growing on top of three smaller shield volcanoes that had coalesced. Two notable events in the mountain's history include a large lava flow which traveled some 18 km to the north east of the peak, and a flow erupted from a rift zone on the flank of the volcano some 320,000 years ago, which was basaltic in nature, marking the most recent dated activity of the volcano. The flow was dated using radiometric methods.
Mount Sanford was first climbed on July 21, 1938 by noted mountaineers Terris Moore and Bradford Washburn, via the still standard North Ramp route up the Sheep Glacier. This route "offers little technical difficulty" and "is a glacier hike all the way to the summit" but is still a serious mountaineering challenge (Alaska Grade 2) due to the altitude and latitude of the peak. The base of the route is usually accessed by air, but landing near the mountain is not straightforward.
On March 12, 1948, Northwest Airlines Flight 4422 crashed into Mount Sanford. All 24 passengers and 6 crew members were killed. The wreckage was quickly covered by snow and was not found again until 1999.