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.
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, but during the 18th and 19th centuries, these were temporary organizations.[1] 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 brigades and brigade combat teams.
Since the authorizations of permanent divisions, the United States Army has raised 128 separate divisions with unique lineages.
American Revolution
George Washington organized the first divisions of the United States Army on 22 July 1775 in Boston, Massachusetts. Arriving to take command of the Siege of Boston, he split the forces there into three divisions, each composed of two brigades of six to seven regiments. These divisions were led by major generals but with no assigned staff. They were primarily administrative but eventually evolved into semi-permanent tactical organizations.[2][3]
American Civil War
During the Civil War, when the first large true field armies in United States history were formed, divisions were the Union Army's basic administrative and organizational unit.[4][5] They were also the smallest "self-sufficient" units, each composed of two to six brigades. These were typically three brigades for infantry divisions and two brigades for cavalry divisions.[6] A division was typically commanded by a major general, but because Congress refused to promote officers past that grade (with the exception of promoting Ulysses S. Grant to lieutenant general in 1864) major generals were also put in charge of field armies and corps, allowing some divisions to be commanded by brigadier generals. Divisions were numbered sequentially within their corps, but were often referred to by the commander's name in official reports.[5]
When the Army of the Potomac was first formed after the disastrous First Battle of Bull Run, the division was initially the largest unit. It consisted of three infantry brigades, a cavalry regiment, and four artillery batteries. However the cavalry and artillery were eventually spun off to their own units. When army corps were formally created in March 1862, half of the divisional artillery units were used to form an artillery reserve of three brigades for the army. After the Peninsula campaign the cavalry were removed from divisional control to form their own brigades under army control, until February 1863 when they were formed into a dedicated Cavalry Corps of three divisions, each with two brigades and assigned horse artillery. Following Chancellorsville all artillery batteries were removed from divisional control to form brigades under corps control.[4][7][8] The evolution of divisions within the Army of the Potomac served as a model by which the other field armies in the Union organized themselves.[9]
In the beginning the division commander was allowed only an assistant adjutant general and three aides-de-camp as their staff.[4] Administrative needs eventually led to the addition of a quartermaster, a commissary of subsistence, an ordnance officer, and a surgeon, all with the rank of major. However, there were no enlisted personnel specifically assigned to support duties, instead requiring either line soldiers be detailed to carry them out or civilian workers employed. The former removed the combat effectiveness of the units they were taken from, while the latter were more difficult to find and replace and tended to be less reliable and obedient.[10]
Designations
Before 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.
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 were inactivated in 1942.
2nd Cavalry Division: Unorganized. A 2nd Cavalry Division was constituted in 1921, but would remain unorganized until World War II.
3rd Cavalry Division: Unorganized. The 3rd Cavalry Division was placed on rolls in 1927 to complete an intended Cavalry Corps, but was never organized.
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.
10th Division – Organized in 1918 as a Regular Army and National Army division for World War I, the 10th Division did not go overseas and demobilized in February 1919 at Camp Funston, Kansas.
14th Division: 1918–1919 – Organized in 1918 as a Regular Army and National Army division for World War I, the 14th Division did not go overseas and demobilized in February 1919 at Camp Custer, Michigan.
15th Division: 1918–1919 – Organized in 1918 as a Regular Army and National Army division for World War I, the 15th Division did not go overseas and demobilized in February 1919 at Camp Logan, Texas
16th Division: 1918–1919 – Organized in 1918 as a Regular Army and National Army division for World War I, the 16th Division did not go overseas and demobilized in March 1919 at Camp Kearny, California.
17th Division: 1918–1919 - Organized in 1918 as a Regular Army and National Army division for World War I, the 17th Division did not go overseas.
94th Division: 1921–1942* (94th Infantry Division) A 94th Division was intended as a Spanish-speaking division recruited in Puerto Rico for World War I, but the assignment was withheld due to political wrangling.
30th Armored Division: 1954–1973. The 30th Armored Division was organized as the result of an agreement between Tennessee and North Carolina to split the 30th Infantry Division.
39th Armored Division: phantom World War II division
6th Infantry Division: 1939–1942* (6th Motorized Division); 1943–1949; 1950–1956; 1967–1968; 1984–1998. The 6th Infantry Division itself was deactivated in 1994, but the 1st Brigade, 6th Infantry Division remained in the active force under that designation until being reflagged as the 172nd Infantry Brigade in 1998.
93rd Infantry Division (Colored): 1942–1946. Although the 93rd Infantry Division shares the same number designation and patch as the previous 93rd Division, the two divisions are otherwise unrelated and do not share lineal ties.
105th Infantry Division: never actually organized during World War II
106th Infantry Division: 1943–1945; 1946–1950. The 106th Infantry Division was never officially added to the troop list following World War II, despite having been almost completely organized in Puerto Rico by 1948; subsequently, the War Department determined the division was not needed and deactivated the division headquarters in 1950.
107th Infantry Division: never actually organized during World War II
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.
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.
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.[11]
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 formations composed of Black soldiers.
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 canceled in 1942.
^Wilson, J. B. (1998). Maneuver and Firepower: The Evolution of Divisions and Separate Brigades. United States: Center of Military History, U.S. Army. Pg. vii
^McGrath, John J. The Brigade: A History, Its Organization and Employment in the US Army. (2004). Fort Leavenworth, KS : Combat Studies Institute, US Army Command and General Staff College. Pg 3
^Shrader, C. R., Newell, C. R. (2011). Of Duty Well and Faithfully Done: A History of the Regular Army in the Civil War. United States: Nebraska. p. 71
Bellanger, Yves J. (2002). US Army Infantry Divisions, 1943–1945, Volume 1: Organisation, Doctrine and Equipment. Solihull: Helion.
Holt, Thaddeus (2004). The Deceivers: Allied Military Deception in the Second World War. New York: Simon & Schuster.
Muschett, James O. (ed.) (2001). The Army. Westport: Hugh Lauter Levin.
Stanton, Shelby L. (2006). World War II Order of Battle: An Encyclopedic Reference to U.S. Army Ground Forces from Battalion through Division, 1939–1946 (Revised Edition). Mechanicsburg: Stackpole.
Stewart, Richard W. (ed.) (2005). American Military History, Volume II: The United States Army in a Global Era, 1917–2003. Washington, D.C.: Government Printing Office.
Tolson, John J. (1989). Airmobility 1961–1971. Washington, D.C.: Government Printing Office.
Wilson, John B. (1987). Armies, Corps, Divisions, and Separate Brigades. Washington, D.C.: Government Printing Office.
1st Cavalry Division: 1921–present
2nd Cavalry Division: Unorganized. A 2nd Cavalry Division was constituted in 1921, but would remain unorganized until World War II..svg){kind=small}
Hawaiian Division: 1921–1941* (24th Infantry Division; see also 25th Infantry Division)
Panama Canal Division: 1921–1932
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