It covers 1.2 square miles (3.1 km2) and contains 4.3 billion cubic feet (120×10^6 m3) of ice.

[2] The glacier starts out near the summit of the volcano at over 14,200 feet (4,300 m).

As the glacier flows west-southwest out of the summit area, it cascades down a steep rocky face as an icefall from 13,200 feet (4,000 m) to 11,000 feet (3,400 m), where the glacier is connected to the South Mowich Glacier to the north in the Sunset Amphitheater.

After the broad expanse of ice at over 8,000 feet (2,400 m), the Tahoma Glacier narrows as it descends around the rocky 7,690-foot (2,344 m) Glacier Island, a sub-peak of Rainier once fully encircled by both the South Tahoma and Tahoma Glaciers.

Leaving the bottleneck in the glacier, the glacier splits; the larger, longer northern arm continues flowing west-southwest and terminates at around 5,500 feet (1,700 m).