| Mount Churchill | |
|---|---|
 U.S. Geological Survey climbing party ascending the Klutlan Glacier en route to Mount Churchill | |
| Highest point | |
| Elevation | 4,744 m (15,564 ft)  |
| Prominence | 1,188 ft (362 m) |
| Coordinates | 61°25′9″N 141°42′55″W / 61.41917°N 141.71528°W |
| Geography | |
  Mount Churchill | |
| Parent range | Saint Elias Mountains |
| Topo map | USGS McCarthy B-2 Quadrangle |
| Geology | |
| Mountain type | Stratovolcano with caldera |
| Volcanic field | Wrangell Volcanic Field |
| Last eruption | 700 AD ± 200 years |
| Climbing | |
| First ascent | August 20, 1951 by R. Gates, J. Lindberg |
| Easiest route | snow climb |
Mount Churchill is a dormant volcano in the Saint Elias Mountains and the Wrangell Volcanic Field (WVF) of eastern Alaska. Churchill and its neighbor Mount Bona are both ice-covered volcanoes with Churchill having a 2.7-by-4.2-kilometre-wide (1.7 mi × 2.6 mi) caldera just east of its summit. There are sparse outcrops of lava flows and tephra, mostly dacite.
Subduction of the Pacific Plate beneath southeastern Alaska has largely ceased during the last one million years, causing a decline of the volcanic activity in the WVF. Churchill appears to be fed by melts derived from a stagnant slab in the mantle, left over by the previous subduction.
The volcano erupted several times during the Holocene. The most notable eruptions are the two White River Ash eruptions, deposited during two of the largest volcanic eruptions in North America during the past two millennia. The northern lobe was emplaced about 1,890 years ago, while the larger eastern lobe erupted in winter 852/853. The White River Ash covers vast expanses of Alaska and western Canada and has been found as far as Europe, and there is evidence that the Athabaskan people migrated out of the region and into the present-day United States as a consequence of the eruption.