Hinman Glacier occupied the north and northwest side of Mount Hinman in Washington’s Alpine Lakes Wilderness and was long a prominent Cascade glacier. In 1971, at about 1.3 square kilometers, it was the largest glacier between Mount Rainier and Glacier Peak. Evidence suggests it may have originated soon after the Cordilleran ice sheet retreated and existed by the time of the Mount Mazama eruption. Warming climate caused its two-part ice mass to shrink, with the western lobe disappearing first and a new lake forming behind its terminal moraine. By August 2022 only remnant ice remained, and in 2023 it was reported extinct, reflecting the broader retreat of Cascade glaciers and affecting late-summer water flows, aquatic life, and watershed users.