USS Idaho ( BB - 42 ) USS " Idaho " ( BB - 42 ) , a , was the fourth ship of the United States Navy to be named for the 43rd state . Her keel was laid down by the New York Shipbuilding Corporation of Camden , New Jersey . She was launched on 30 June 1917 sponsored by Miss Henrietta Amelia Simons , granddaughter of Idaho Governor Moses Alexander ; and commissioned on 24 March 1919 , Captain Carl Theodore Vogelgesang in command . Inter - War period . " Idaho " sailed on 13 April 1919 for shakedown training out of Guantanamo Bay , and after returning to New York City received President of Brazil Epitácio Pessoa for the voyage to Rio de Janeiro . Departing on 6 July with her escort , the battleship arrived Rio on 17 July . From there she set course for the Panama Canal , arriving Monterey , California , in September to join the Pacific Fleet . She joined other dreadnoughts in training exercises and reviews , including a Fleet Review by President of the United States Woodrow Wilson on 13 September . In 1920 , the battleship carried Secretary of the Navy Josephus Daniels and the Secretary of the Interior " ( either Franklin K . Lane or John B . Payne ) " on an inspection tour of Alaska . Upon her return from Alaska on 22 July 1920 , " Idaho " took part in fleet maneuvers off the California coast and as far south as Chile . She continued this important training until 1925 , taking part in numerous ceremonies on the West Coast during the interim . Two of the original 14 / 51 cal gun s were removed in 1922 . " Idaho " took part in the fleet review held by President Warren Harding in Seattle shortly before his death in 1923 . The battleship sailed on 15 April 1925 for Hawaii , participated in war games until 1 July , and then got underway for Samoa , Australia , and New Zealand . On the return voyage , " Idaho " embarked gallant Commander John Rodgers and his seaplane crew after their attempt to fly to Hawaii , arriving San Francisco , California on 24 September . For the next six years , " Idaho " operated out of San Pedro , California , on training and readiness operations off California and in the Caribbean Sea . She sailed from San Pedro on 7 September 1931 for the East Coast , entering Norfolk Navy Yard on 30 September for modernization . The earlier anti - aircraft guns were replaced by eight / 25 cal gun s . The veteran battleship also received better armor , " blister " antisubmarine protection , better machinery , and tower masts during this extensive overhaul , and was readied for many more years of useful naval service . After completion on 9 October 1934 , the ship conducted shakedown in the Caribbean before returning to her home port , San Pedro on 17 April 1935 . As war clouds gathered in the Pacific , the fleet increased the tempo of its training operations . " Idaho " carried out fleet tactics and gunnery exercises regularly until arriving with the battle fleet at Pearl Harbor on 1 July 1940 . The ship sailed for Hampton Roads on 6 June 1941 to perform Atlantic neutrality patrol , a vital part of US policy in the early days of the European fighting . She moved to Iceland in September to protect American advance bases and was on station at Hvalfjörður when the Japanese attack on Pearl Harbor on 7 December catapulted America into the war . World War II . " Idaho " and sister ship departed Iceland two days after Pearl Harbor to join the Pacific Fleet , and arrived at San Francisco , California , via Norfolk , Virginia , and the Panama Canal on 31 January 1942 . She conducted additional battle exercises in California waters and out of Pearl Harbor until October 1942 , when she entered Puget Sound Navy Yard to be regunned . The original secondary battery of / 51 cal guns was removed to make room for anti - aircraft machine guns . Upon completion of this work , " Idaho " again took part in battle exercises , and sailed on 7 April 1943 for operations in the Aleutian Islands . There she was flagship of the bombardment and patrol force around Attu , where she gave gunfire support to the United States Army landings on 11 May . During the months that followed , she concentrated on Kiska , culminating in an assault on 15 August . The Japanese were found to have evacuated the island in late July , thus abandoning their last foothold in the Aleutians . " Idaho " returned to San Francisco on 7 September to prepare for the invasion of the Gilbert Islands . Moving to Pearl Harbor , she got underway with the assault fleet on 10 November and arrived off Makin Atoll on 20 November . She supported the fighting ashore with accurate gunfire support and antiaircraft fire , remaining in the Gilberts until sailing for Pearl Harbor on 5 December . Next on the Pacific timetable was the invasion of the Marshall Islands , and the veteran battleship arrived off Kwajalein early on 31 January 1944 to soften up shore positions . Again , she hurled tons of shells into Japanese positions until 5 February , when the outcome was one of certain victory . After replenishing at Majuro , she bombarded other islands in the group , then moved to Kavieng , New Ireland for a diversionary bombardment on 20 March . " Idaho " returned to the New Hebrides on 25 March , and after a short stay in Australia arrived Kwajalein with a group of escort carriers on 8 June . From there , the ships steamed to the Marianas , where " Idaho " began a pre - invasion bombardment of Saipan on 14 June . With the landing assault underway on 15 June , the battleship moved to Guam for bombardment assignments . As the American fleet destroyed Japanese carrier air power in the Battle of the Philippine Sea from 19 – 21 June , " Idaho " protected the precious transport area and reserve convoys . After returning to Eniwetok from 28 June to 9 July , the ship began preinvasion bombardment of Guam on 12 July , and continued the devastating shelling until the main assault eight days later . As ground troops battled for the island , " Idaho " stood offshore providing vital support until anchoring at Eniwetok on 2 August . The ship continued to Espiritu Santo and entered a floating dry dock on 15 August for repairs to her " blisters " . After landing rehearsals on Guadalcanal in early September , " Idaho " moved to Peleliu on 12 September and began bombarding the island , needed as a staging base for the invasion of the Philippines . Despite the furious bombardment , Japanese entrenchments gave assault forces stiff opposition , and the battleship remained off Peleliu until 24 September providing the all - important fire support for advancing Marines . She then sailed for Manus and eventually to Bremerton , Washington , where she arrived for needed repairs on 22 October . The / 25 cal guns were replaced by 10 / 38 cal gun s in single enclosed mounts ( she was the only ship of her class to receive this modification ) . This was followed by battle practice off California . " Idaho " ' s mighty guns were needed for the next giant amphibious assault on the way to Japan . She sailed from San Diego on 20 January 1945 to join a battleship group at Pearl Harbor . After rehearsals , she steamed from the Marianas on 14 February for the invasion of Iwo Jima . As Marines stormed ashore on 19 February , " Idaho " was again blasting enemy positions with her big guns , and fired star shells at night to illuminate the battlefield . She remained off Iwo Jima until 7 March , when she underway for Ulithi and the last of the great Pacific assaults – Okinawa . " Idaho " sailed on 21 March as part of Rear Admiral Deyo ' s Gunfire and Covering Group and flagship of Bombardment Unit 4 . She arrived offshore on 25 March and began silencing enemy shore batteries and pounding installations . The landings began on 1 April , and as the Japanese made a desperate attempt to drive the vast fleet away with " kamikaze " attacks , " Idaho " s gunners shot down numerous planes . In a massed attack on 12 April , the battleship shot down five " kamikazes " before suffering damage to her port blisters from a near - miss . After temporary repairs , she sailed 20 April and arrived at Guam five days later . The veteran of so many of the landings of the Pacific quickly completed repairs and returned to Okinawa on 22 May to resume fire support . " Idaho " remained until 20 June , then sailed for battle maneuvers in Leyte Gulf until hostilities ceased on 15 August . " Idaho " made her triumphal entry into Tokyo Bay with occupation troops on 27 August , and was anchored there during the signing of the surrender onboard the on 2 September . Four days later she began the long voyage to the East Coast of the United States , steaming via the Panama Canal to arrive at Norfolk on 16 October . She decommissioned on 3 July 1946 and was placed in reserve until sold for scrap on 24 November 1947 to Lipsett , Incorporated , of New York City .