US 45th Infantry Division

US 45th Infantry Division
User:Stannered · Public domain · source
Unit name	45th Infantry Division
Dates	1924–1968
Country	United States
Branch	National Guard
Type	Infantry
Nickname	"Thunderbird"
Notable commanders	Maj. Gen. Terry de la Mesa Allen Sr., Maj. Gen. Orlando Ward, Maj. Gen. Raymond S. McLain
Identification symbol label	Shoulder sleeve insignia

US 45th Infantry Division was a National Guard formation composed principally of personnel from Oklahoma, Arizona, Colorado, and New Mexico that served in major campaigns of World War II and the Korean War, participating in amphibious assaults, mountain warfare, and urban combat. The division earned multiple unit citations and individual awards including the Distinguished Service Cross (United States), the Medal of Honor, and foreign decorations while campaigning in theaters that involved coordination with formations such as the First United States Army, the Seventh United States Army, and allied forces from United Kingdom, France, and Soviet Union. Its heritage influenced later National Guard (United States) reorganizations and state military museums.

Formation and Early History

The division originated from state militia reorganizations after World War I when units from Oklahoma National Guard, Arizona National Guard, Colorado National Guard, and New Mexico National Guard were federalized and combined under the National Guard Bureau and the United States Army in the interwar period. Constituted in 1923 and organized in 1924, the formation trained at locations including Fort Sill, Camp Bowie, and Fort Bliss while participating in Army maneuvers and civil missions such as disaster relief after the 1927 Mississippi Floods and responses to labor disturbances during the Great Depression. Command relationships involved the War Department and periodic federal activations under legislation like the Militia Act of 1903 and later wartime authority.

World War II Service

Federalized for World War II in 1940, the division deployed to the European Theater of Operations where it took part in the Sicily Campaign and the Italian Campaign including amphibious landings at Salerno with the Allied invasion of Sicily (Operation Husky) and subsequent operations involving the Seventh United States Army and the Allied Force Headquarters. Reassigned for the Normandy Campaign follow-on operations, the division fought in the Rhineland Campaign, engaged in the liberation of towns in France, and participated in the final drives into Germany alongside formations such as the U.S. Seventh Army and units of the French Army. Throughout, 45th units cooperated with logistics commands like the Services of Supply (United States Army) and intelligence assets including Army Ground Forces reconnaissance elements.

Postwar Reorganization and Korean War Era

After Victory in Europe Day, the division demobilized and returned to state control, then was redesignated and reorganized under the National Security Act of 1947 and the postwar structure overseen by the Department of Defense. During the Korean War mobilization, elements of the division were federalized, trained, and in some cases deployed to support logistic and replacement operations for formations engaged in the Korean Peninsula conflict alongside units such as the Eighth United States Army and multinational commands led by Douglas MacArthur. The era saw changes in infantry doctrine influenced by experiences from Okinawa and Cold War contingency planning for NATO and United Nations commitments.

Cold War Activities and National Guard Service

In the Cold War period the division served as a strategic reserve under the Continental Army Command and later National Guard Bureau guidance, participating in annual exercises with the U.S. Army Reserve, rotations influenced by the Pentomic reorganization and the later ROAD (Reorganization Objective Army Divisions) concept. Units conducted training at installations including Fort Hood, Camp Roberts, and state armories and were periodically federalized during crises such as civil disturbances and state emergencies, coordinating with agencies like the Department of Justice and state governors under the Insurrection Act when activated for domestic missions.

Structure, Insignia, and Traditions

The division's triangular organization included infantry regiments, field artillery battalions, engineer combat battalions, and support units aligned with contemporary orders of battle like those used by the U.S. Army in the 1940s and 1950s, with subordinate formations including regiments that traced lineage to units such as the 179th Infantry Regiment and the 180th Field Artillery Regiment. The distinctive red and yellow shoulder sleeve insignia featuring a stylized Native American thunderbird motif reflected ties to Southwestern states and was regulated by the Institute of Heraldry (U.S. Army). Traditions included annual state military ceremonies, veterans' associations such as the division's 45th Infantry Division Association, and commemorations at museums like the Oklahoma Military Museum.

Notable Engagements and Casualties

Notable battles included the Battle of Salerno, the Sicily landings (Operation Husky), actions in the Italian Campaign such as the assaults on the Gustav Line, engagements in the Normandy Campaign follow-ons, and later operations across the Rhine River into Germany. The division suffered significant casualties during assaults and urban combat, with multiple soldiers awarded the Medal of Honor and numerous unit citations from the Army and allied governments; the human cost was memorialized by monuments at battle sites in Italy and France and recorded in official Army casualty statistics and after-action reports.

Legacy and Commemoration

The division's legacy is preserved by memorials, veterans' organizations, and state historical centers, with artifacts displayed at institutions including the National Infantry Museum, the Oklahoma Historical Society, and state capitol exhibits in Oklahoma City and Phoenix, Arizona. Its lineage influenced later National Guard reorganizations culminating in conversion to separate brigade structures that fed into formations such as the 45th Infantry Brigade Combat Team, and its combat record is cited in studies by military historians at universities like West Point and research centers including the U.S. Army Center of Military History. The division remains commemorated in annual observances, regimental reunions, and educational programs that involve archival holdings at the National Archives and Records Administration.

Category:Infantry divisions of the United States Army Category:Military units and formations established in 1924 Category:Military units and formations disestablished in 1968