USS King County (LST-857) was an LST-542-class tank landing ship built for the United States Navy during World War II.

After embarking ordnance and construction troops and loading equipment at Iloilo, Panay, and Batangas, Luzon, she sailed in convoy for Japan on 20 September.

Departing Yokohama on 15 December, she steamed via Saipan and Pearl Harbor to the United States and arrived at San Francisco on 25 January 1946.

She departed San Diego on 31 July, reached Pearl Harbor on 11 August, and began supply runs under Service Force, Pacific Fleet.

She arrived Pearl Harbor on 11 July; and, after serving briefly as inter-island transport, she departed on 18 August to support the effort to repel Communist aggression in South Korea.

After embarking men and equipment of the 1st Marine Engineer Battalion, she sortied on 10 September as part of an amphibious attack convoy bound for Inchon, South Korea.

Assigned to Task Element 90.32, LST-857 arrived off Inchon on 15 September while a heavy air-sea bombardment pounded enemy shore positions.

Late that afternoon, she closed "Red Beach" under heavy mortar and machine gun fire to take part in landings which were designed to spearhead an Allied offensive northward.

For daring bravery and heroic performance of duty on "Red Beach", the aggressive and intrepid tank landing ships, including LST-857, received the Navy Unit Commendation.

On the 22nd she sailed for Sasebo where she arrived on 26 October to prepare for shuttle duty along the vital water supply line between Japan and Korea.

Between 17 August and 12 September she made a supply run to the Marshalls; then she sailed for the West Coast on 1 October, arriving at Oakland, California, on the 11th.

She entered the Mare Island Naval Shipyard on 12 October 1957 and began conversion to an experimental guided missile test ship.