U.S. Army Divisions in World War II
This site provides a history of all 91 U.S. Army divisions that served in World War II from 1939 to 1945. Information includes: commanding generals, campaigns fought, division chronicle, and campaign maps.
INFANTRY DIVISIONS
ARMORED DIVISIONS
AIRBORNE DIVISIONS
MEDITERRANEAN THEATER
PACIFIC THEATER
EUROPEAN THEATER
A comprehensive visual history of all 91 divisions, U.S. Army Divisions in World War II charts the formation and achievements of the infantry, armored, airborne, mountain and cavalry forces. This chart can be zoomed in and is available for purchase at HistoryShots.com.
The U.S. Army
During World War II about 16,000,000 personnel served in the U.S. Military. Approximately 11,200,000 or 70% served in the U.S. Army; 4,200,000 served in the Navy; and 660,000 served in the Marines.
The U.S. Army was re-organized into three forces in March 1942:
Army Ground Forces (AGF). According to the The Army Almanac, "Its mission was to provide ground force units properly organized, trained and equipped for combat operations." About 4,400,000 personnel were part of the Army Ground Forces during the war. They sustained about 80% of the U.S. Army casualties.
Army Service Forces (ASF). The ASF, originally called Services of Supply, was responsible suppling and servicing the U.S. Army. Organizations under ASF included: corps of engineers, quartermaster corps, medical corps, signal corps, chemical warfare service, ordnance department, and the military police.
Army Air Forces (AAF). The AAF was responsible for the training and making ready the air component of the U.S. Army. The Army Air Forces became an independent service (U.S. Air Force) in 1947.
At it's peak in March 1945, the U.S. Army had 8,200,000 personnel. A comparison of Army Ground Forces strength with total U.S. Army strength is provided below.
The Army Ground Forces
Personnel in the Army Ground Forces were grouped into two areas: divisional forces and non-divisional forces. In March 1945, there was about 1,200,000 personnel assigned to divisions and 1,500,000 to non-divisional units.
The core combat arm of the Army Ground Forces was organized around the division formation. The division was created to be the smallest Army organization capable of performing independent operations. Ninety-one divisions were formed by the U.S. Army in World War II. In general, a division contained about 15,000 troops. See below for a complete breakdown of a division.
Non-divisional forces included service units and some additional combat troops not initially assigned to a division. Note: most service units were allocated across all U.S. Army organizations. For example, both the Army Service Forces and Army Ground Forces had engineer units. In addition, engineer units were part of divisions while other engineer units were part of non-divisional personnel.
Divisions Overview
Combat troops of the U.S. Army are classified by the weapons and methods used in combat:
There were 5 types of divisions: infantry, mountain, armored, airborne, and cavalry.
91 divisions were mobilized during the war: 68 infantry divisions, 1 mountain division, 16 armored divisions, 5 airborne divisions, and 2 cavalry divisions.
All divisions were activated in the United States except for the following divisions: Philippine (activated in the Philippines), Hawaiian (activated in Hawaii and renamed the 24th division), 25th (activated in Hawaii from troops of the Hawaiian division), and Americal (activated in New Caledonia.)
There were three major theaters of operation during the war: Pacific (22 divisions were deployed to the Pacific), Mediterranean (15 divisions), and Europe (61 divisions). Seven divisions served in both the Mediterranean and European Theaters (1st, 3rd, 9th, 36th, 45th infantry divisions; 82nd Airborne; and 2nd Armored.)
Two divisions were disbanded or deactivated before the end of the war: the Philippine division was destroyed and disbanded on 10 April 1942; and the 2nd Cavalary division was activated and inactivated twice: 15 Apr 41 to 15 Jul 42 and 23 Feb 43 to 10 May 44.
Three divisions did not enter combat: 98th Infantry division, 13th Airborne division, and the 2nd Cavalary division.
By June 1946, 74 divisions were inactivated or disbanded leaving 17 divisions on active duty.
All divisions of the U.S. Army originated from the following four sources:
Regular Army
National Guard
Organized Reserves
Army of the United States
The numbering of divisions followed a pattern established in 1917 during World War I. The numbers 1 to 25 were reserved for the Regular Army; numbers 26 to 45 for the National Guard; and numbers 46 to 106 for the Army of the U.S. However, there were a number of exceptions. The two airborne divisions, 82nd and 101st, were redesignated Regular Army when they converted from infantry to airborne divisions. The 25th was formed from troops of the Hawaiin division and was classified as an Army of the U.S. division. The 42nd division was a National Guard division in World War II but was mobilized as an Army of the U.S. division.