Which Mount Rainier glacier is the source of the Nisqually River?

Nisqually Glacier is the source of the Nisqually River. The glacier descends the southwestern side of Mount Rainier in Washington and supplies meltwater to the river system below.

Nisqually is one of Mount Rainier’s larger glaciers and can be viewed from the Paradise area of Mount Rainier National Park. Its position on the mountain’s southwestern face makes it one of the volcano’s most familiar and accessible glaciers, while its meltwater connection gives it importance beyond scenery.

The glacier has an unusually long scientific record. Its terminus has been measured annually since 1918, making it one of the longest-studied glaciers on Mount Rainier. In May 1970, researchers measured average movement of about 29 inches per day.

Like many glaciers on Rainier, Nisqually reached a major maximum during the nineteenth-century Little Ice Age and later retreated. Its area fell from 3.871 square miles in 1896 to 1.584 square miles in 2021. Quiz-takers may confuse it with Tahoma, Carbon or Emmons glaciers, all of which also drain Mount Rainier, but Nisqually is the named source of the Nisqually River.