The Greenwell Glacier is a major tributary glacier, 45 miles (72 km) long, draining northwest between the Mirabito Range and the Everett Range to enter Lillie Glacier below Mount Works, in northwest Victoria Land, Antarctica. This geographical feature was first mapped by the United States Geological Survey from surveys and from U.S. Navy aerial photography, 1960–63, and was so named by the Advisory Committee on Antarctic Names for Commander Martin D. Greenwell, U.S.