| Mount Defiant | |
| Elevation Ft: | 8348 |
| Elevation Ref: | [1] |
| Prominence Ft: | 98 |
| Isolation Mi: | 0.73 |
| Range: | Chugach Mountains |
| Location: | Chugach National Forest Valdez-Cordova Borough Alaska, United States |
| Map: | USA Alaska |
| Label Position: | left |
| Coordinates: | 61.2547°N -147.1267°W |
| Topo: | USGS Anchorage B-1 |
Mount Defiant is an 83480NaN0 elevation glaciated summit located 320NaN0 northwest of Valdez in the Chugach Mountains of the U.S. state of Alaska. This remote mountain is situated 2.50NaN0 east-northeast of Columbia Peak, 6.50NaN0 south of Mount Einstein, near the head of Columbia Glacier's Second Branch, on land managed by Chugach National Forest. Mount Defiant was named in 1957 by members of the Chugach Mountains Expedition which was sponsored by the Arctic Institute of North America, because the rugged ice-covered peak defied all their attempts to find a route to the summit.[2] The mountain's name was officially adopted in 1965 by the U.S. Board on Geographic Names.[3]
Based on the Köppen climate classification, Mount Defiant is located in a subarctic climate zone with long, cold, snowy winters, and mild summers.[4] Weather systems coming off the Gulf of Alaska are forced upwards by the Chugach Mountains (orographic lift), causing heavy precipitation in the form of rainfall and snowfall. Temperatures can drop below −20 °C with wind chill factors below −30 °C. This climate supports hanging glaciers on the slopes and the immense Columbia Glacier surrounding this mountain. The months May through June offer the most favorable weather for climbing or viewing.