Rainbow Division

Rainbow Division
-- Steven Williamson (HiB2Bornot2B) - talk ▓▒░ Go Big Blue! ░▒▓ 15:22, 13 August · Public domain · source
Unit name	Rainbow Division
Caption	Shoulder sleeve insignia
Dates	1917–present
Country	United States
Branch	National Guard
Type	Infantry
Size	Division
Notable commanders	Douglas MacArthur, Leonard Wood, Douglas C. MacArthur
Garrison	New York, New Jersey, Indiana, Connecticut, Vermont
Nickname	The Rainbow

Rainbow Division

The Rainbow Division was a United States Army infantry division formed during World War I that drew units and personnel from multiple State Guard formations across the United States. It served in major Western Front offensives, was reorganized during the Interwar Period, deployed again in World War II operations and later served as a National Guard formation through the Cold War and into the modern era. Its cross-state composition, distinctive insignia, and legacy link it to numerous American Expeditionary Forces campaigns and postwar military structures.

Formation and Early History

The division was organized in 1917 under the aegis of the National Army and the War Department as part of the rapid expansion following the United States declaration of war on Germany. Recruiting drew heavily from New York (state), New Jersey, Pennsylvania, Indiana, Connecticut, Vermont, Illinois, Massachusetts, Rhode Island, Maine, and other state National Guards, creating a cross-country composition intended to symbolize national unity. The division trained at camps such as Camp Mills and Camp Upton and incorporated officers and enlisted men with experience from prior conflicts like the Philippine–American War and the Spanish–American War.

World War I Service

Upon arrival in France, the unit joined the American Expeditionary Forces under General John J. Pershing and participated in key operations on the Western Front, including the Champagne-Marne, Aisne-Marne Offensive, and the Meuse-Argonne Offensive. The division fought alongside French Army and British Expeditionary Force formations, integrating into multinational logistics and command structures and suffering heavy casualties during trench warfare, artillery barrages, and combined-arms assaults. Commanders such as Major General Douglas MacArthur gained prominence for actions during these campaigns, and units from the division received decorations including the Distinguished Service Cross and foreign awards like the Légion d'honneur.

Interwar Period and Reorganization

After Armistice of 11 November 1918, the division returned to the United States and underwent demobilization at cantonments including Camp Upton before elements were reconstituted in the National Guard. During the interwar years the division's brigades and regiments were administered through state adjutant generals and aligned with the Chief of the National Guard Bureau directives. Reorganization efforts aligned the division with evolving doctrine influenced by studies of the Great War and by observers of British Army and French Army postwar reforms, preparing it for potential future mobilization amid shifting international tensions such as those surrounding the Treaty of Versailles and interwar arms limitations.

World War II and Later Combat Operations

Elements of the division were federalized and redesignated during World War II, with units serving in theaters including the European Theater of Operations and supporting campaigns that intersected with formations like the U.S. First Army and the U.S. Ninth Army. Post-1945 reorganizations reflected changes from triangular to pentomic to ROAD structures under Department of the Army guidance, and the division's descendant units participated in later operations and crises including readiness activities linked to conflicts such as the Korean War and deployments in support of Cold War commitments.

Cold War and National Guard Role

Throughout the Cold War the division existed primarily as a National Guard headquarters and set of subordinate regiments and battalions, coordinating training with federal agencies including the Department of Defense and participating in exercises with NATO partners. Its state-based units were activated for domestic emergencies, civil support, and federal mobilizations, interacting with agencies such as the Federal Emergency Management Agency and state governors' offices under provisions of the Posse Comitatus Act constraints. The division's lineage continued through redesignations tied to broader National Guard reforms and force structure changes driven by the Total Force Policy.

Insignia, Nickname, and Traditions

The division's shoulder sleeve insignia—a multicolored arc—was designed to symbolize a national formation spanning many states and was associated with the nickname "The Rainbow". Ceremonial traditions linked to the division include annual veterans' reunions, memorials at sites such as Meuse-Argonne American Cemetery, and preservation efforts by organizations like the U.S. Army Center of Military History and state historical societies. Unit marches and regimental colors reflect honors awarded during World War I and subsequent periods, while museums and monuments in states including New Jersey and Indiana commemorate its service.

Notable Personnel and Legacy

Prominent figures who served with the division or its successor formations include Douglas MacArthur, who rose to national prominence, and other officers who later held commands in the U.S. Army or civilian posts. The division's actions influenced interwar military thought recorded in publications from institutions such as the United States Military Academy and contributed to memorial literature maintained by groups like the American Legion and the Veterans of Foreign Wars. Its legacy endures in unit lineages, regimental histories, battlefield preservation initiatives, and the broader narrative of American participation in World War I and 20th-century conflicts.

Category:Infantry divisions of the United States Army Category:United States Army divisions of World War I