Thomas Island is a large island in Highjump Archipelago

Highjump Archipelago

Highjump Archipelago is a group of rocky islands, rocks and ice rises about 50 nautical miles long and from 5 to 15 nautical miles wide, lying generally north of the Bunger Hills and extending from the Taylor Islands, close northwest of Cape Hordern, to a prominent group of ice rises which...

, 6 nautical miles (11 km) long and from 1 to 3 nautical miles (6 km) wide, lying near the center of the main cluster of islands off the north flank of the Bunger Hills

Bunger Hills

Bunger Hills or Bunger Lakes or Bunger Oasis is a coastal range on the Knox Coast in Wilkes Land in Antarctica, consisting of a group of moderately low, rounded coastal hills, overlain by morainic drift and notably ice free throughout the year, lying south of the Highjump Archipelago.The Bunger...

. Mapped from air photos taken by U.S. Navy Operation Highjump, 1946-47, and named by the 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) for Lieutenant (j.g.) Randolph G. Thomas, U.S. Navy, hydrographic officer with U.S. Navy Operation Windmill, 1947-48, who served as surveyor with the astronomical control parties.