The 24th Infantry Division was an infantry division of the United States Army that was deactivated in October 1996. Formed during World War II from the disbanding Hawaiian Division, the division saw action throughout the Pacific theater, first fighting in New Guinea before landing on the Philippine islands of Leyte and Luzon, driving Japanese forces from them. Following the end of the war, the division participated in occupation duties in Japan, and was the first division to respond at the outbreak of the Korean War. For the first 18 months of the war, the division was heavily engaged on the front lines with North Korean and Chinese forces, suffering over 10,000 casualties. It was withdrawn from the front lines to the reserve force for the remainder of the war after the second battle for Wonju, but returned to Korea for patrol duty at the end of major combat operations.

After its deployment in the Korean War, the division was active in Europe and the United States during the Cold War. It was based at Fort Stewart, Georgia and later reactivated at Fort Riley, Kansas. It did not see combat again until the Persian Gulf War, when it faced the Iraqi military. A few years after that conflict, it was inactivated as part of the post-Cold War U.S. military drawdown of the 1990s. The division was reactivated in October 1999 as a formation for training and deploying U.S. Army National Guard units before its deactivation in October 2006.

The 24th Infantry Division traces its lineage to Army units activated in Hawaii. It was activated under the Square Division Table of Organization and Equipment (TO&E) on 1 March 1921 as the Hawaiian Division at Schofield Barracks, Oahu. The division insignia is based on the taro leaf, emblematic of Hawaii. The 21st Infantry Regiment and the 22nd Infantry Regiment was assigned to the Division, both of which had been assigned to the US 11th Infantry Division prior to 1921.

The entire Hawaiian Division was concentrated at a single location during the next few years, allowing it to conduct more effective combined arms training. It was also manned at higher personnel levels than other divisions, and its field artillery was the first to be motorized.

Between August and September 1941, the Hawaiian Division's assets were reorganized to form two divisions under the new Triangular Division TO&E. Its brigade headquarters were disbanded and the 27th and 35th Infantry Regiments were assigned to the new 25th Infantry Division. Hawaiian Division headquarters was redesignated as Headquarters, 24th Infantry Division on 1 October 1941. The 24th Infantry Division also received the Hawaiian Division's Shoulder Sleeve Insignia, which was approved in 1921.

The division was then centered around three infantry regiments: the 19th Infantry Regiment and the 21st Infantry Regiment from the old Hawaiian Division, and the 299th Infantry Regiment from the Hawaii National Guard. In July 1942, the 299th Infantry was inactivated after its ranks were depleted by the transfer of many Nisei (second-generation Japanese-Americans) to form the 100th Infantry Battalion, and the 25th Infantry Division's 298th Infantry Regiment was reassigned to the 24th. Also part of the division were the 13th Field Artillery Battalion, the 52nd Field Artillery Battalion, the 63rd Field Artillery Battalion, the 11th Field Artillery Battalion, the 24th Signal Company, the 724th Ordnance Light Maintenance Company, the 24th Quartermaster Company, the 24th Reconnaissance Troop, the 3rd Engineer Combat Battalion, the 24th Medical Battalion, and the 24th Counterintelligence Corps Detachment.

The 24th Infantry Division was among the first US Army divisions to see combat in World War II and among the last to stop fighting. The division was on Oahu, with its headquarters at Schofield Barracks, when the Japanese launched their Attack on Pearl Harbor on 7 December 1941 and the unit suffered some casualties during the attack. Among these casualties were Sgt. Paul J. Fadon (killed in a truck 10 miles north of Schofield Barracks), Pvt. Walter R. French, Pfc. Conrad Kujawa, Pvt. Torao Migita (killed by friendly fire in downtown Honolulu), and Corporal Theodore J. Lewis (who became the 24th Infantry Division's first soldier killed during WWII). The division was then charged with the defense of northern Oahu, where it built an elaborate system of coastal defenses throughout 1942. In July 1942, the 299th Infantry Regiment was replaced by the 298th Infantry Regiment. One year later, this regiment was replaced by the 34th Infantry Regiment from the Hawaiian Department Reserve. The 34th Infantry remained with the 24th Infantry Division until the end of the war. As an active component unit, the 34th was easier to deploy than the reserve component units, which were less trained.

In May 1943, the 24th Infantry Division was alerted for movement to Australia, and it completed the move to Camp Caves, near Rockhampton, on the eastern coast of Australia by 19 September 1943. Once deployed, it began intensive combat training. After training, the division moved to Goodenough Island on 31 January 1944, to prepare for Operation Reckless, the amphibious capture of Hollandia, Netherlands New Guinea (now Jayapura, Papua province, Indonesia).