45th Infantry Division (United States)

45th Infantry Division (United States)
User:Stannered · Public domain · source
Unit name	45th Infantry Division
Caption	Shoulder sleeve insignia
Dates	1924–1968
Country	United States
Branch	United States Army
Type	Infantry
Role	Ground combat
Size	Division
Garrison	Oklahoma City
Nickname	Thunderbird Division
Motto	"Semper Anticus"
Notable commanders	Major General Joe B. Sanborn

45th Infantry Division (United States) was a National Guard United States Army infantry division that served in the interwar period, World War II, the Korean War, and the early Cold War before inactivation during the Vietnam War era. Raised from National Guard units in the Southwestern United States, the division deployed to the European Theater of Operations in 1944 and later to the Korean Peninsula in 1951, earning campaign streamers and decorations including the Distinguished Unit Citation.

Formation and Early History

The division was constituted from National Guard elements in the states of Oklahoma, Colorado, New Mexico, and Arizona during the interwar mobilizations following World War I and the reorganization under the National Defense Act of 1920. Early leadership emphasized readiness alongside contemporaries such as the 34th Infantry Division, 29th Infantry Division, 36th Infantry Division, and 41st Infantry Division. Training took place at posts and camps including Camp Gruber, Camp Bowie, Camp Barkeley, and annual encampments at Fort Sill and Fort Bliss. The division adopted the Thunderbird shoulder sleeve insignia and recruited veterans of the Mexican Expedition, Pancho Villa Expedition, and Great Depression-era militia duty.

World War II Service

Federalized in 1940 as part of the U.S. mobilization before Pearl Harbor, the division trained with formations like the 82nd Airborne Division, 1st Infantry Division, and 3rd Infantry Division at stateside installations such as Fort Benning and Fort Jackson. After shipment to the United Kingdom and subsequent amphibious training in the English Channel embarkation ports, the division landed in Italy and later in France, participating in major operations including the Sicilian Campaign, the Naples-Foggia campaign, the Anzio landings, and the drive through the Rhineland. The division fought alongside the British Eighth Army, U.S. Fifth Army, II Corps (United States), and allied units including the French Expeditionary Corps. In combat the division engaged in battles at Salerno, Monte Cassino, Rome-Arno campaign, and the liberation of towns in Southern France and the Rhine region, confronting elements of the Wehrmacht and Fallschirmjäger. Decorations were awarded to soldiers who served with units such as the 157th Infantry Regiment, 179th Infantry Regiment, and 180th Infantry Regiment, supported by the 45th Reconnaissance Troop and divisional artillery like the 160th Field Artillery Battalion.

Postwar Reorganization and Cold War Era

Returning to state control after Victory in Europe Day, the division reconstituted under the National Guard Bureau and reorganized amid broader Army reforms including the Pentomic and later ROAD structures. During the early Cold War the division maintained readiness alongside other National Guard divisions such as the 40th Infantry Division and 34th Infantry Division, participating in joint exercises with NATO forces and training at Cold War-era installations including Camp Polk and Fort Chaffee. Personnel exchanges, officer professional education at institutions like the United States Army War College and Command and General Staff College, and procurement programs under the Department of Defense modernized equipment from World War II-era small arms to Cold War artillery and armored vehicles.

Korean War and Later Deployments

Federalized for the Korean War in 1951, the division deployed elements and replacements to the Korean Peninsula theater to reinforce formations including X Corps (United States), Eighth United States Army, and United Nations commands that included contingents from United Kingdom, Canada, and Australia. Units provided infantry, artillery, and support roles during counteroffensives and static defense operations against the Korean People's Army and Chinese People's Volunteer Army. After Korea, the division returned to state control and served as a strategic reserve during crises such as the Berlin Crisis of 1961 and provided mobilization assets during the early years of the Vietnam War, before inactivation and reallocation of personnel to formations like the 45th Field Artillery Group and successor National Guard brigades.

Organization and Unit Composition

Organizationally the division comprised infantry regiments including the 157th Infantry Regiment (Oklahoma Army National Guard), 179th Infantry Regiment (Oklahoma) and 180th Infantry Regiment (Oklahoma), reconnaissance units, engineer battalions, signal companies, medical battalions, and divisional artillery such as the 160th Field Artillery Regiment. Support elements included the 45th Quartermaster Company, 45th Ordnance Battalion, and 45th Military Police Company, with attachment and coordination with armored units like the 70th Tank Battalion during combined-arms operations. Changes through the Combat Arms Regimental System and later Regimental System altered battalion alignments, while National Guard state headquarters in Oklahoma City and adjutants general oversaw administration and allocations.

Insignia, Traditions, and Legacy

The division's Thunderbird shoulder sleeve insignia reflected Indigenous motifs similar to other unit heraldry and became a symbol invoked in ceremonies at Oklahoma State Capitol events and veteran reunions. Traditions included annual observances with organizations such as the American Legion, Veterans of Foreign Wars, and state historical societies. Distinguished alumni and commanders who served in the division went on to roles in United States Congress, state government, and military education at the United States Military Academy. The division's combat record is preserved in museums like the Oklahoma History Center and archives at the National Archives and Records Administration, influencing National Guard doctrine and commemoration through monuments on battlefields such as those in Normandy, Anzio Beachhead, and the Korean War Veterans Memorial.

Category:Infantry divisions of the United States Army Category:United States Army divisions of World War II Category:United States Army divisions of the Korean War Category:Military units and formations established in 1924