Duffey Peak is part of the Joffre Group, which is a subset of the Lillooet Ranges of the Coast Mountains.

The nearest higher neighbor is Slalok Mountain, 4 km (2 mi) to the northeast and the two peaks are connected by Two Goat Ridge.

Topographic relief is significant as the summit rises over 2,000 meters (6,560 feet) above Lillooet Lake in four kilometers (2.5 miles).

[5] Most weather fronts originate in the Pacific Ocean, and travel east toward the Coast Mountains where they are forced upward by the range (Orographic lift), causing them to drop their moisture in the form of rain or snowfall.

As a result, the Coast Mountains experience high precipitation, especially during the winter months in the form of snowfall.