Flett Glacier, Mountain glacier in Mount Rainier National Park, Washington, US.

Flett Glacier consists of two separate ice sections on the northwestern side of Mount Rainier at different elevations. The eastern and western lobes together form a continuous ice body in this mountain region.

The glacier was named after botanist John B. Flett, who made the first recorded climb of Little Tahoma in 1895. This naming honors his early exploration of the mountain region.

The glacier's name honours John B. Flett, the botanist who climbed Little Tahoma in 1895; the two ice lobes on Observation Rock's flank carry his name on maps of Mount Rainier. Meltwater from the ice feeds the Puyallup River, linking the high slopes to the valleys below.

Access requires a park permit for Mount Rainier National Park, particularly during the warmer months from May through September. Visitors should prepare for high-altitude conditions and bring proper mountaineering gear.

Flett Glacier is split into two ice lobes on Observation Rock, a 8,364 ft (2,549 m) subsidiary peak of Mount Rainier: an eastern lobe between roughly 7,600 and 7,300 ft and a smaller western lobe near 7,200 ft. The name honours botanist John B. Flett, who climbed Little Tahoma in 1895.