Argosy Mountain is an 8,155-foot summit in northwestern Montana's Flathead Range, within the Great Bear Wilderness on Flathead National Forest land. Rising steeply above nearby terrain, it stands about 2,350 feet above Argosy Creek within a mile, giving it strong local relief. Water from its slopes drains north to the Middle Fork Flathead River through Roaring, Argosy, and Dolly Varden creeks. The mountain lies in a subarctic climate with long, very cold winters and short, cool to mild summers. Its sedimentary rock formed in shallow seas from the Precambrian through the Jurassic, then was uplifted beginning about 170 million years ago by the Lewis Overthrust.