Divisions of the United States Army

This list of United States Army divisions is divided into three eras: 1911–1917, 1917–1941, and 1941–present. These eras represent the major evolutions of army division structure (there have been several minor changes during these times). The 1911–1917 era lists divisions raised during the Army's first attempts at modernizing the division, prior to the authorization of permanent divisions, and the 1917–1941 era lists the first permanent divisions, prior to advent of specialized (armored, airborne, etc.) divisions. The 1941–present era lists all of the divisions organized, raised, or authorized since then.

As much as possible, divisions are only listed in the eras in which they were first created. Some divisions, such as the 1st Cavalry Division, are listed in multiple eras, as their organizations were drastically changed from one era to the next. Many divisions overlap the years listed in the era categories, mainly due to the slow pace in which they were deactivated, inactivated, or otherwise disbanded.

It should also be noted that several divisions have existed under multiple designations, such as the 10th Mountain Division (10th Light Division (Alpine), 10th Infantry Division). Additionally, several divisions with the same numerical designations were completely separate and unrelated divisions (there have been two 5th Divisions, for instance).

History

Divisions in the United States Army have existed since the American Revolution when, on 22 July 1775, George Washington organized three divisions in Boston, Massachusetts. Early American divisions, up until the American Civil War, were primarily temporary organizations, with the basis of the United States Army being brigades and regiments.

During the Civil War, the war in which formed the first large true armies in United States history, divisions were formed primarily to support Army corps, and were usually numbered as 1st, 2nd, and 3rd Division of the pertaining corps.

The concept of the permanent United States Army division was formulated and put to the test following the turn of the 20th century. In 1916, the permanent division would finally be authorized by Congress, resulting in a dramatic change in the Army's force structure. For the first time, the division was the base element of the United States Army and remained as such until the Global War on Terrorism, when the Army switched its emphasis to brigade and regimental combat teams.

Since the authorizations of permanent divisions, the United States Army has raised 128 separate divisions with unique lineages.

Designations

Prior to 1941, only cavalry divisions were specifically designated; infantry divisions were simply designated by "Division". Following the advent of the armored division, infantry divisions became officially designated by "Infantry Division" (with the 25th Infantry Division being the first constituted by the adjutant general as such). All of the 1917–1941 (non-cavalry) divisions, with the exceptions of the 10th through 20th and 101st Divisions, would be redesignated as Infantry Divisions at some point in the 1941–present era.

Other than the aforementioned Armored, Cavalry, and Infantry, the only official Army division designations are Air Assault (one test division), Airborne, Light (three test divisions in World War II), Motorized (briefly authorized from 1942 to 1943), and Mountain. For lineage purposes, the 101st Airborne Division maintains its designation as an airborne division, though it is currently organized as an air assault division.

Divisions listed with an additional identifier in parentheses ("alpine" or "test", for example) existed only with that identifier. Divisions that have held multiple additional identifiers, such as the 1st Cavalry ("airmobile", "heavy") and the 9th Infantry ("light", "motorized"), are left unidentified, regardless of their current additional identifier.

An unspecified division today refers to a United States Army Reserve training division.

Divisions of the United States Army (1911–17)

Regular Army 1913–16
National Guard 1914–17

National Defense Act of 1916

The National Defense Act of 1916 provided that the "Army of the United States" would consist of the Regular Army, the Volunteer Army, the Officers' Reserve Corps, the Enlisted Reserve Corps, the National Guard in the service of the United States, and such other land forces as were or might be authorized by Congress. The president was to determine both the number and type of National Guard units that each state would maintain. Both the Regular Army and the National Guard were to be organized, insofar as practicable, into permanent brigades and divisions.

Divisions of the United States Army (1917 to 1941)

Cavalry divisions

In 1940, the National Guard voluntarily withdrew their allotment of the 21st through 24th Cavalry Divisions, partially in response to the Army's decision that the National Guard did not need four Cavalry Divisions and the Army's unwillingness to allot the National Guard armored divisions. The 61st through 66th Cavalry Divisions existed primarily as officer billets with enlisted cadre; they were dropped from the activation rolls and disbanded in 1942.

Infantry divisions

Shoulder Sleeve Insignia of World War I Divisions
(the 15th, 16th, 17th, 19th, and 20th Divisions never officially selected insignia)

Various elements of the 4th through 9th Divisions remained on active duty until those divisions' full activation prior to World War II.

The 76th through 91st and 94th through 104th Divisions existed primarily as officer billets with enlisted cadre; they were not completely reactivated until America's entry into World War II.

The infantry brigades, field artillery brigades, and several other of the subordinate units of the Panama Canal, Hawaiian, and Philippine Divisions were numbered accordingly with what should have been the 10th, 11th, and 12th Divisions.

Divisions of the United States Army (1941 to present)

Air assault divisions

Airborne divisions

Armored divisions

Cavalry divisions

Infantry divisions

The 105th and 107th Infantry Divisions were intended to be negro divisions of the Army of the United States; however, due to a shortage of available manpower, their activations were canceled in 1942.

Light divisions

Motorized divisions

Mountain divisions

Reserve training divisions

In an attempt to maintain its divisions, the Army Reserve transformed several of its combat divisions into training divisions; these divisions were still designated as infantry divisions until authorized as "divisions (training)" by the adjutant general in 1959.

Divisions planned but never actually formed during World War II

At the time of the Japanese attacks on Pearl Harbor, Wake Island, and the Philippines, the United States Army was composed of 37 divisions, including the Philippine Division. Initially, necessary mobilization was estimated to be as high as 350 divisions, but the Army ultimately settled on a 100-division plan.

This relatively low number (compared to the high estimates) was partially due to the army's policy of assigning many combat units, particularly artillery and tank destroyer units, directly to corps and higher-level commands. These non-divisional units numbered approximately 1.5 million soldiers, enough personnel to man roughly 100 more divisions. The strategic philosophy was that such units could be assigned to divisions on an as-needed basis, and would allow divisions to remain as mobile and flexible as possible. By the end of 1943, U.S. Army strength stood at more than 70 divisions.

Allied gains in 1942 and 1943 resulted in a further contraction of U.S. mobilization, and the last wartime division, the 65th Infantry Division, was activated on 16 August 1943. In all, 91 divisions served in the U.S. Army in World War II. When the decision was made to halt the increase in divisions, 12 more divisions were still on the rolls, but would not be organized, though several of these would be organized following the war. They were the 15th Airborne Division, the 18th, 21st and 22nd Armored Divisions, the 19th Armored Division, which was in fact activated following the war, the 61st, 62nd, 67th, 68th, 72nd, 73rd, and 74th Infantry Divisions, and the 105th and 107th Infantry Divisions, which were intended to be Negro formations.

Unique among the 14 unorganized divisions, the 15th Airborne Division was not only a victim of the decision to set the size of the Army at 89 divisions (the 2nd Cavalry Division had been deactivated during the war and the Philippine Division was destroyed as a result of the Japanese victory in the Philippines), but also because it had become evident that the Army Air Forces lacked enough transport aircraft to support a sixth airborne division. The 13th Airborne Division never saw combat for this very reason.

The 105th and 107th Infantry Divisions were to join the 92nd and 93rd Infantry Divisions as Negro divisions. A shortage of manpower resulted in the activation of the 105th and 107th being cancelled in 1942.

See also

Notes

    References

    Further reading

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