King Peninsula is an ice-covered peninsula, 100 miles long and 20 miles wide, lying south of Thurston Island

Thurston Island

Thurston Island is an ice-covered, glacially dissected island, long, wide and in area, lying a short way off the NW end of Ellsworth Land, Antarctica. It is the third largest island of Antarctica, after Alexander Island and Berkner Island...

 and forming the south side of Peacock Sound

Peacock Sound

Peacock Sound is an ice-filled sound, long and wide, separating Thurston Island from the Eights Coast of Ellsworth Land in Antarctica. The sound is occupied by the western part of the Abbot Ice Shelf, and is therefore not navigable by ships....

. It projects from the continental ice sheet and trends west between the Abbot Ice Shelf

Abbot Ice Shelf

The Abbot Ice Shelf is an ice shelf long and wide, bordering Eights Coast from Cape Waite to Phrogner Point in Antarctica. Thurston Island lies along the northern edge of the western half of this ice shelf; other sizable islands lie partly or wholly within this shelf.The ice shelf was sighted by...

 and Cosgrove Ice Shelf

Cosgrove Ice Shelf

Cosgrove Ice Shelf is a long by wide ice shelf, occupying the inner part of the embayment between King Peninsula and Canisteo Peninsula, Antarctica. It was mapped from air photos taken by U.S. Navy Operation Highjump, 1946–47, and named by the Advisory Committee on Antarctic Names for...

 to terminate at Amundsen Sea

Amundsen Sea

The Amundsen Sea is an arm of the Southern Ocean off Marie Byrd Land in western Antarctica. It is bounded by Cape Flying Fish, the northwestern tip of Thurston Island to the east and Cape Dart on Siple Island to the west. East of Cape Flying Fish starts the Bellingshausen Sea. West of Cape Dart is...

. The feature was photographed from the air by USN Operation Highjump

Operation Highjump

Operation Highjump , officially titled The United States Navy Antarctic Developments Program, 1946-1947, was a United States Navy operation organized by RADM Richard E. Byrd Jr. USN, , Officer in Charge, Task Force 68, and led by RADM Richard H. Cruzen, USN, Commanding Officer, Task Force 68....

, 1946–47, and was plotted from these photos as a long island, or possible peninsula. Photos taken by USN in 1966 show it is a peninsula.

King Peninsula was 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 Fleet Admiral Ernest J. King, USN, Chief of Naval Operations from 1942–45, who approved the preliminary work for Operation Highjump.