World War I Divisions: Then and Now

Divisions as “permanent” elements of the U.S. Army establishment date to World War I. The chart below lists the 64 divisions organized, in whole or in part, during the war. It includes the divisions’ organization dates and whom they are perpetuated by today. It does not include any divisions formed after 11 November 1918 and not all of those listed deployed overseas. For each division, a link is provided to its most recent lineage and honors information, if available. This is drawn from two sources. The first is the lineage and honors information posted to the CMH website, which contains the most recent lineage information prepared by CMH at the request of currently active units. Additional lineages will be added if they are prepared. For most other Regular Army and Army Reserve units which have not been disbanded, lineage information is available in CMH Publication 60-7, Armies, Corps, Divisions, and Separate Brigades. Be aware that the lineage and heraldic information in this publication are only current as of its publication in 1999. As a courtesy to our users, we have extracted the relevant pages and posted them as PDFs. National Guard lineage information from CMH Publication 60-7 have not been posted due to being out of date. Finally, be aware that the lineage information reflected below is only for the division headquarters. It does not include that of their brigades or subordinate units, which have their own separate lineages.

World War I Divisions: An Overview

[The following is extracted from CMH Pub 60-14, Maneuver and Firepower: The Evolution of Divisions and Separate Brigades, pages 23, 40-42, 47, and 73].

At the opening of the twentieth century, following the hasty organization and deployment of the army corps during the War with Spain, the Army's leadership realized that it needed to create permanent combined arms units trained for war. Accordingly, senior officers worked toward that goal until the nation entered World War I. Their efforts reflected the principal mission of the Army at the time: to defend the vast continental United States and its modest insular empire in the Caribbean Sea and Pacific Ocean. During this period the infantry division replaced the army corps as the basic combined arms unit. Growing in size and fire power, it acquired combat support and service elements, along with an adequate staff, reflecting visions of a more complex battlefield environment. The cavalry division, designed to achieve mobility rather than to realize its combined arms potential, underwent changes similar to those of the infantry division. Army leaders also searched for ways to maintain permanent divisions that could take the field on short notice. That effort accomplished little, however, because of traditional American antipathy toward standing armies.

Between the War with Spain and the United States' intervention in World War I, the Army's principal mission was to defend the national territory and its insular possessions. During this period the Army tested and adopted the infantry division as its basic combined arms unit. The underlying planning assumption was that the infantry division would fight in the United States. This meant, in turn, that one of the principal determinants of a division's size was road-marching speed. The cavalry division, although not neglected, remained more or less a theoretical unit. As the Army mobilized for the Mexican border crisis and look note of trends in foreign armies during the initial campaigns of World War I, its leaders became increasingly convinced of the need to create permanent tactical divisions. Congress approved them in 1916, but the nation entered World War I before these plans had been perfected. Events during the next two years, however, profoundly affected divisional organizations, the infantry division in particular. For the first lime in the nation's experience, the United States Army mobilized a huge expeditionary force to fight overseas in Western Europe, a mission for which it was thoroughly unprepared. The day of the old constabulary army was over. Faced with threats to national security of hitherto unimagined scope emanating from the Old World, the nation had to revolutionize its army to wage war against a formidable continental opponent. The necessity for an effective combined arms organization would force extraordinary changes in its entire structure.

World War I, an unprecedented conflict, forced fundamental changes in the organization of United States Army field forces. The infantry division remained the Army's primary combined arms unit, but the principles governing its organization took a new direction because of French and British experiences in trench warfare. Column length or road space no longer controlled the size and composition of the in fan try division; instead, fire power, supply, and command and control became paramount. The cavalry division received scant attention as the European battle field offered few opportunities for its use.

By Armistice Day, 11 November 1918, the Army had fielded 1 cavalry division, I provisional infantry division, and 62 infantry divisions. Of this total, 42 infantry divisions and the provisional division deployed to Europe (see table 6), with one, the 8th Division, not arriving until after the fighting had ended. On the Western Front in France, 29 divisions (7 Regular Army, 11 National Guard, and 11 National Army) fought in combat. Of the others, 7 served as depot divisions, 2 of which were skeletonized, and 5 were stripped of their personnel for replacements in combat units, laborers in rear areas, or expeditionary forces in North Russia or Italy. The provisional black division was broken up, but its four infantry regiments saw combat. Starting from a limited mobilization base, this buildup, lasting eighteen months, was a remarkable achievement.

Despite the difficulties, World War I brought about more coordination among the combat arms, combat support, and combat service organizations in the infantry division than ever before. Infantry could not advance without support from engineers and artillery; artillery could not continue to fire without a constant supply of ammunition. Transportation and signal units provided the vital materiel and command connections, while medical units administered to the needs of the wounded. This complex type of combined arms unit became possible because of advances in technology, weapons, communications, and transportation.

The adoption of the unwieldy square division, however, proved to be less than satisfactory. Pershing's staff believed that a di vision of 28,000 would conserve the limited supply of trained officers, maximize firepower, and sustain itself effectively in combat. In practice, the square division lacked mobility. Its deficiencies became apparent during the important Meuse-Argonne offensive, when American divisions bogged down and suffered excessive casualties. The successes and failures of the infantry division's organization set the stage for a debate that would surround it for the next twenty years.

Additional Resources

• Armies, Corps, Divisions, and Separate Brigades by John B. Wilson (CMH Publication 60-7)
• Maneuver and Firepower: The Evolution of Divisions and Separate Brigades by John B. Wilson (CMH Publication 60-14)
• Order of Battle of the United States Land Forces in the World War (CMH Publications 23-1 to 23-24) [Note: These volumes contain more detailed information on division elements and overseas service]