USS Jefferson County (LST-845) was an LST-542-class tank landing ship built for the United States Navy during World War II.

USS LST-845 was laid down by the American Bridge Company, Ambridge, Pennsylvania, on 23 October 1944; launched on 7 December 1944; sponsored by Mrs. B. F. Fairless; and commissioned at New Orleans, Louisiana, on 1 January 1945.

Steaming via Subic Bay, she reached Lingayen Gulf on 7 October to embark more occupation troops for transportation to Japan.

In response to the invasion of South Korea by North Korean troops on 25 June 1950, LST-845 departed San Diego on 10 August and sailed to the Far East to bolster the American effort to repel this Communist aggression.

She departed Inchon on 15 October and steamed to the eastern coast of Korea to carry cargo from Pusan to Wonsan and Hŭngnam.

Following the entrance of Communist China into the Korean War, LST-845 supported the evacuation of Hŭngnam and made three runs south to Pusan.

Arriving Sasebo, Japan, on 10 July, she spent more than six months in Japanese and Korean waters bolstering the naval supply line to South Korea.

She reached Yokosuka on 25 February; and during the next five months cargo runs and amphibious exercises sent her from Japan to Iwo Jima, Okinawa, and Inchon.

In addition to transporting military cargo, she carried civilian refugees seeking to escape from Communist domination in North Vietnam.

After returning to Yokosuka on 20 October, LST-845 sailed for the United States on 7 November and arrived San Diego on 12 December.

She arrived Yokosuka on 13 September and resumed cargo runs and amphibious exercises which carried her along the Japanese coast to Okinawa, Hong Kong, and the Philippines.