USS Addison County (LST-31) was an LST-1-class tank landing ship built for the United States Navy during World War II. Named for Addison County, Vt., she was the only U.S. Naval vessel to bear the name.
LST-31 was laid down on 2 February 1943 at Pittsburgh, Pennsylvania by the Dravo Corporation; launched on 5 June 1943; sponsored by Mrs. Maurice Endres; accepted by the Navy and placed in reduced commission on 10 July 1943; and sailed to New Orleans where she was placed in full commission on 21 July 1943 with Lieutenant John D. Schneidau, Jr., USNR, in command.
The new tank landing ship got underway on 29 July for Panama City, Florida where she conducted a series of beaching exercises. LST-31 returned to New Orleans on 7 August to take on cargo for transportation to the Pacific. After a brief port call at Guantanamo Bay, Cuba the vessel transited the Panama Canal in August and joined the Pacific Fleet. She then continued on to San Diego, California where she arrived in September.
After participating in beaching exercises in the San Diego area, the ship stopped at Port Hueneme and at San Francisco, California to take on cargo. She left the west coast on 15 October bound for Hawaii, reached Pearl Harbor on the 25th, and began unloading. When this task was completed, LST-31 again weighed anchor in November and shaped a course for the Gilbert Islands. As a member of 5th Amphibious Force, the ship was slated to take part in the assault on Makin Island. LST-31 arrived off Makin and began discharging troops and cargo ashore. She remained off that atoll until 3 December, when she got underway to return to Pearl Harbor. Shortly after her arrival, the vessel entered the Pearl Harbor Navy Yard for repairs and alterations. While her engines were being overhauled, additional 40-millimeter and 20-millimeter guns were installed. The yard period ended in early January 1944, and the refurbished vessel then took part in training exercises off Maui in preparation for the forthcoming invasion of the Marshall Islands.