A broad glacier flowing into Amundsen Sea about 30 mi E of Mount Murphy, Marie Byrd Land. Though imperfectly delineated, the glacier has tremendous flow and in January 1966 had formed a large floating glacier tongue (40 mi long) and an extensive grounded iceberg tongue (70 mi long). Together, these features extend into Amundsen Sea more than 100 mi and inhibit E-W navigation by ships. Mapped by USGS from surveys and U.S. Navy air photos, 1959-66. Named by US-ACAN in association with Thwaites Glacier Tongue.