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. In addition, a number of carefully restored vintage US Army division maps and route charts are displayed.
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.
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:
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.
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.
Combat troops of the U.S. Army are classified by the weapons and methods used in combat:
All divisions of the U.S. Army originated from the following four sources:
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.
Army Battle Casualties and Non-battle Deaths in World War II, Final Report, 1 December 1941 - 31 December 1946.
Greenfield, Palmer, & Wiley. US Army in World War II, The Organization of Ground Combat Troops
The Army Almanac: A Book of Facts Concerning the Army of the United States; Order of Battle, U.S. Army, World War II