Underwood Glacier is a channel glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

 about 15 miles (24 km) long, flowing to the Antarctic coast between Reist Rocks

Reist Rocks

Reist Rocks is a small group of rocks on the Antarctic coast, 8 nautical miles west of Snyder Rocks. First mapped from air photos taken by U.S. Navy Operation Highjump . Named by Advisory Committee on Antarctic Names for Wilbur H. Reist, tractor driver with U.S...

 and Cape Nutt

Cape Nutt

Cape Nutt is a mostly ice-covered cape with several rock outcrops at the extremity, forming the west side of the entrance to Vincennes Bay. The position of Cape Nutt correlates closely with the eastern end of "Knox's High Land" as charted as a coastal landfall in 1840 by the United States...

. It was mapped in 1955 by G. D. Blodgett from aerial photographs taken by U.S. Navy Operation Highjump in 1947 and named by Advisory Committee on Antarctic Names

Advisory Committee on Antarctic Names

The Advisory Committee on Antarctic Names is an advisory committee of the United States Board on Geographic Names responsible for recommending names for features in Antarctica...

 (US-ACAN) after Lieutenant Thomas Joseph Underwood, Jr., USMC, who served on the sloop Vincennes of the United States Exploring Expedition

United States Exploring Expedition

The United States Exploring Expedition was an exploring and surveying expedition of the Pacific Ocean and surrounding lands conducted by the United States from 1838 to 1842. The original appointed commanding officer was Commodore Thomas ap Catesby Jones. The voyage was authorized by Congress in...

 (1838-42) under Lieutenant Charles Wilkes

Charles Wilkes

Charles Wilkes was an American naval officer and explorer. He led the United States Exploring Expedition, 1838-1842 and commanded the ship in the Trent Affair during the American Civil War...

.