U . S . Army Birthdays The U . S . Army was founded on 14 June 1775 , when the Continental Congress authorized enlistment of riflemen to serve the United Colonies , " for one year . The 14 June date is when Congress adopted " the American continental army " after reaching a consensus position in The Committee of the Whole . This procedure and the desire for secrecy account for the sparseness of the official journal entries for the day . The record indicates only that Congress undertook to raise ten companies of riflemen , approved an enlistment form for them , and appointed a committee ( including Washington and Schuyler ) to draft rules and regulations for the government of the army . The delegates ' correspondence , diaries , and subsequent actions make it clear that they really did much more . They also accepted responsibility for the existing New England troops and forces requested for the defense of the various points in New York . The former were believed to total 10 , 000 men ; the latter , both New Yorkers and Connecticut men , another 5 , 000 . At least some members of Congress assumed from the beginning that this force would be expanded . That expansion , in the form of increased troop ceilings at Boston , came very rapidly as better information arrived regarding the actual numbers of New England troops . By the third week in June delegates were referring to 15 , 000 at Boston . When on 19 June Congress requested the governments of Connecticut , Rhode Island , and New Hampshire to forward to Boston " such of the forces as are already embodied , towards their quotas of the troops agreed to be raised by the New England Colonies , " it gave a clear indication of its intent to adopt the regional army . Discussions the next day indicated that Congress was prepared to support a force at Boston twice the size of the British garrison , and that it was unwilling to order any existing units to be disbanded . By the first week in July delegates were referring to a total at Boston that was edging toward 20 . 000 . Maximum strengths for the forces both in Massachusetts and New York were finally established on 21 and 22 July , when solid information was on hand . These were set , respectively , at 22 , 000 and 5 , 000 men , a total nearly double that envisioned on 14 June . The " expert riflemen " authorized on 14 June were the first units raised directly as Continentals . Congress intended to have the ten companies serve as a light infantry force for the Boston siege . At the same time it symbolically extended military participation beyond New England by allocating 6 of the companies to Pennsylvania , 2 to Maryland , and 2 to Virginia . Each company would have a captain , 3 lieutenants , 4 sergeants , 4 corporals , a drummer ( or horn player ) , and 68 privates . The enlistment period was set at one year , the norm for the earlier Provincials , a period that would expire on 1 July 1776 . Responsibility for recruiting the companies was given to the three colonies ' delegates , who in turn relied on the county committees of those areas noted for skilled marksmen . The response in Pennsylvania ' s western and northern frontier counties was so great that on 22 June the colony ' s quota was increased from six to eight companies , organized as a regiment . On 25 June the Pennsylvania delegates , with authority from the Pennsylvania Assembly , appointed field officers for the regiment . Since there was no staff organization , company officers and volunteers performed the necessary duties . On 11 July delegate George Read secured the adoption of a ninth company that his wife ' s nephew had organized in Lancaster County . In Virginia Daniel Morgan raised one company in Frederick County , and Hugh Stephenson raised another in Berkeley County . Michael Cresap ' s and Thomas Price ' s Maryland companies were both from Frederick County . All thirteen companies were organized during late June and early July . They then raced to Boston , where their frontier attitudes created disciplinary problems . Selection of Commanders . The inclusion of troops from outside New England gave a continental flavor to the army at Boston . A desire to broaden the base of support for the war also led John Adams to work for the appointment of a southerner as the commander of all the continental forces , raised , or to be raised , for the defense of American liberty . On 15 June Congress unanimously chose George Washington . Washington had been active in the military planning committees of Congress and by late May had taken to wearing his old uniform . His colleagues believed that his modesty and competence qualified him to adjust to the " Temper & Genius " of the New England troops . Washington was given the rank of General and Commander in Chief . Congress clearly respected Washington , for it granted him extensive powers which combined functions of a regular British commander with the military responsibilities of a colonial governor . His instructions on 20 June told him to proceed to Massachusetts , " take charge of the army of the United Colonies , " and capture or destroy all armed enemies . His was also to prepare and to send to Congress an accurate strength return of that army . On the other hand , instructions to keep the army obedient , diligent , and disciplined were rather vague . The Commander in Chief ' s right to make strategic and tactical decisions on purely military grounds was limited only by a requirement to listen to the advice of a council of war . Within a set troop maximum , including volunteers , Washington had the right to determine how many men to retain , and he had the power to fill temporarily any vacancies below the rank of colonel . Permanent promotions and appointments were reserved for the colonial governments to make . Although sectional politics were involved in Washington ' s selection , in strictly military terms he was in fact the best - qualified native American . He had begun his military career in 1752 in the Virginia militia as one of four regional adjutants responsible for training . During the first phase of the French and Indian War , he served with gallantry as Edward Braddock ' s volunteer aide at the battle of the Monongahela , and later as the commander of Virginia ' s two Provincial regiments defending the colony ' s frontiers . In 1758 he commanded a brigade composed of Virginia , Maryland , and Pennsylvania units on John Forbes ' expedition against Fort Duquesne . Washington was the only American in that war to command so large a force . The experience of these years taught him the importance of discipline , marksmanship , and professional study . Exposure to Forbes ' ideas on adapting European tactics to the American wilderness also contributed significantly to his military education . Above all , he came to the conclusion that only unyielding commitment to hard work and attention to administrative detail could keep troops in the field . On 16 June , the day after Washington ' s appointment , Congress authorized a variety of other senior officers for its new army . Details were again settled by the Committee of the Whole . Positions for five major staff officers were established : an Adjutant General , a Commissary of Musters , a Paymaster General , a Commissary General , and a Quartermaster General . These officers were expected to assist the Commander in Chief with the administration of the " grand army . " The forces allocated to New York already were considered a separate department and were authorized their own deputy quartermaster general and deputy paymaster general . A military secretary and 3 aides for Washington , a secretary for the separate department , and 6 engineers ( 3 for each force ) completed the staff . Congress also created the ranks of major general and brigadier general . The number of generals remained uncertain for several days as Congress debated . Between 17 and 22 June it finally decided on 4 major generals , each having 2 aides , and 8 brigadier generals . These totals allowed each colony raising troops to have a share of the patronage . Congress then took steps for issuing paper money to finance the army , and on 30 June it adopted the Articles of War . Selection of the subordinate generals and senior staff officers led to political maneuvering as delegates sought appointments for favorite sons . On 17 June Congress elected Artemas Ward and Charles Lee as the first and second major generals and Horatio Gates as the Adjutant General . Ward received seniority because he was in command at Boston and because Massachusetts had furnished the largest contingent of troops . Ward was a Harvard graduate with many years of political experience . After two years of active duty as a field officer in the French and Indian War , he had compiled an excellent record as a militia administrator . Lee and Gates were professional English officers in their forties who were living in Virginia on the half - pay ( inactive ) list . Both had served in the French and Indian War and were associates of politicians in England and America who opposed British policies . Lee had also seen service in Portugal and in the Polish Army . Gates had ended the Seven Years ' War as a major in the Caribbean . His appointment as Adjutant General ( with the rank of brigadier general ) reflected Congress ' hope that his staff experience would enable him to provide Washington with strong administrative assistance . On 19 June two more major generals were appointed to satisfy other colonies ' contributing large troop contingents . Philip Schuyler , a New York delegate with close ties to Washington , was expected to take command of the troops in his colony . A member of one of New York ' s leading families , the 42 - year - old Schuyler had been a major in the French and Indian War , specializing in logistics . His experience , political connections , and extensive business interests in Albany were particularly valuable in his new command . Connecticut ' s delegation could not agree on a nominee for that colony ' s major general . In the end Israel Putnam ' s status as a folk hero outweighed consideration of seniority , and he received the appointment . Putnam , at 57 , had seen extensive service in the French and Indian War , rising to the rank of lieutenant colonel . He had also been an early , vocal leader of the Connecticut Sons of Liberty . The process of selecting brigadier generals on 22 June was the product of a compromise . Congress allotted these appointments in proportion to the number of men contributed by each colony and followed the recommendations of the colony ' s delegates in the actual selection . Congress , however , created problems by ignoring seniority and status . When it elected Massachusetts ' Seth Pomeroy , William Heath , and John Thomas as the first , fourth , and sixth brigadier generals , respectively , Thomas felt he had been slighted . The situation was resolved when Pomeroy declined the appointment , citing age , before Washington handed out the commissions . Congress then made Thomas the first brigadier general , although it did not fill the vacancy created by Pomeroy ' s withdrawal . Thomas , a surgeon militiamen , and former Provincial born in 1724 , had gained combat experience primarily in medical roles . Heath , thirteen years younger , was strictly a product of the militia . Richard Montgomery of New York became the second ranking brigadier general . Born in Ireland in 1738 and educated at Dublin ' s Trinity College , he had entered the British Army in 1756 . After combat service in North America and in the Caribbean , he resigned in 1772 when he failed to receive a promotion to major . He moved to New York , married into the powerful Livingston family , and in 1775 won election to the New York Provincial Congress . Montgomery ' s appointment was intended to complement Schuyler ' s logistical and administrative skills with combat experience . David Wooster and Joseph Spencer of Connecticut became the third and fifth brigadier generals . Born in 1711 and educated at Yale , Wooster had served in Connecticut ' s navy during King George ' s War . He later commanded a regiment in the French and Indian War . Spencer , three years younger , had also served in both wars . The two men initially refused to serve under Putnam , disputing his seniority , and had to be coaxed into accepting their commissions . Delegate John Sullivan of New Hampshire , a 35 - yearold lawyer , became the seventh brigadier general instead of Nathaniel Folsom . Nathanael Greene of Rhode Island completed the list . In retrospect , the June 1775 decision of the Continental Congress to create the Continental Army seems remarkably free from political strife . Delegates of all shades of opinion supported each step , and arguments largely concerned technical details . Unanimity resulted from a conviction that British actions required defensive measures and from carefully worded compromises . Those individuals committed to the ideal of the citizen - soldier saw Congress ' adoption of the short - term New England force as an acceptance of a yeoman army . Others , remembering practical lessons of the colonial wars , believed that they were forming an army based on the Provincial model . Officer selection was another area of compromise ; the fact that Washington and Schuyler were given blank commissions from Congress to distribute to the regimental officers confirmed local selections while retaining a nominal national level of appointment . Basic branches . Infantry , 14 June 1775 . Ten companies of riflemen were authorized by a resolution of the Continental Congress on 14 June 1775 . However , the oldest Regular Army infantry regiment , the 3d , was constituted on 3 June 1784 , as the First American Regiment . Adjutant General ' s Corps , 16 June 1775 . The post of Adjutant General was established 16 June 1775 , and has been continuously in operation since that time . The Adjutant General ' s Department , by that name , was established by the act of 3 March 1813 , and was redesignated the Adjutant General ' s Corps in 1950 . Corps of Engineers , 16 June 1775 . Continental Congress authority for a " Chief Engineer for the Army " dates from 16 June 1775 . A corps of Engineers for the United States was authorized by the Congress on 11 March 1779 . The Corps of Engineers as it is known today came into being on 16 March 1802 , when the President was authorized to " organize and establish a Corps of Engineers . . . that the said Corps . . . shall be stationed at West Point in the State of New York and shall constitute a Military Academy . " A Corps of Topographical Engineers , authorized on 4 July 1838 , was merged with the Corps of Engineers on March 1863 . Finance Corps , 16 June 1775 . The Finance Corps is the successor to the old Pay Department , which was created in June 1775 . The Finance Department was created by law on 1 July 1920 . It became the Finance Corps in 1950 . Quartermaster Corps , 16 June 1775 . The Quartermaster Corps , originally designated the Quartermaster Department , was established on 16 June 1775 . While numerous additions , deletions , and changes of function have occurred , its basic supply and service support functions have continued in existence . Air Defense Artillery and Field Artillery , 17 November 1775 . The Continental Congress unanimously elected Henry Knox " Colonel of the Regiment of Artillery " on 17 November 1775 . The regiment formally entered service on 1 January 1776 . Armor , 12 December 1776 . The Armor branch traces its origin to the Cavalry . A regiment of cavalry was authorized to be raised by the Continental Congress Resolve of 12 December 1776 . Although mounted units were raised at various times after the Revolution , the first in continuous service was the United States Regiment of Dragoons , organized in 1833 . The Tank Service was formed on 5 March 1918 . The Armored Force was formed on 10 July 1940 . Armor became a permanent branch of the Army in 1950 . Ordnance Corps , 14 May 1812 . The Ordnance Department was established by act of Congress on 14 May 1812 . During the Revolutionary War , ordnance material was under supervision of the Board of War and Ordnance . Numerous shifts in duties and responsibilities have occurred in the Ordnance Corps since colonial times . It acquired its present designation in 1950 . Signal Corps , 21 June 1860 . The Signal Corps was authorized as a separate branch of the Army by act of Congress on 3 March 1863 . However , the Signal Corps dates its existence from 21 June 1860 , when Congress authorized the appointment of one signal officer in the Army , and a War Department order carried the following assignment : " Signal Department — Assistant Surgeon Albert J . Myer to be Signal Officer , with the rank of Major , 27 June 1860 , to fill an original vacancy . " Chemical Corps , 28 June 1918 . The Chemical Warfare Service was established on 28 June 1918 , combining activities that until then had been dispersed among five separate agencies of Government . It was made a permanent branch of the Regular Army by the National Defense Act of 1920 . In 1945 , it was redesignated the Chemical Corps . Military Police Corps , 26 September 1941 . A Provost Marshal General ' s Office and Corps of Military Police were established in 1941 . Prior to that time , except during the Civil War and World War I , there was no regularly appointed Provost Marshal General or regularly constituted Military Police Corps , although a " Provost Marshal " can be found as early as January 1776 , and a " Provost Corps " as early as 1778 . Transportation Corps , 31 July 1942 . The historical background of the Transportation Corps starts with World War I . Prior to that time , transportation operations were chiefly the responsibility of the Quartermaster General . The Transportation Corps , essentially in its present form , was organized on 31 July 1942 . Military Intelligence , 1 July 1962 . Intelligence has been an essential element of Army operations during war as well as during periods of peace . In the past , requirements were met by personnel from the Army Intelligence and Army Security Reserve branches , two - year obligated tour officers , one - tour levies on the various branches , and Regular Army officers in the specialization programs . To meet the Army ' s increased requirement for national and tactical intelligence , an Intelligence and Security Branch was established in the Army effective 1 July 1962 , by General Orders No . 38 , 3 July 1962 . On 1 July 1967 , the branch was redesignated as Military Intelligence . Aviation , 12 April 1983 . Following the establishment of the U . S . Air Force as a separate service in 1947 , the Army began to develop further its own aviation assets ( light planes and rotary wing aircraft ) in support of ground operations . The Korean War gave this drive impetus , and the war in Vietnam saw its fruition , as Army aviation units performed a variety of missions , including reconnaissance , transport , and fire support . After the war in Vietnam , the role of armed helicopters as tank destroyers received new emphasis . In recognition of the growing importance of aviation in Army doctrine and operations , Aviation became a separate branch on 12 April 1983 , and a full member of the Army ' s combined arms team . Special Forces , 9 April 1987 . The first Special Forces unit in the Army was formed on 11 June 1952 , when the 10th Special Forces Group was activated at Fort Bragg , North Carolina . A major expansion of Special Forces occurred during the 1960s , with a total of eighteen groups organized in the Regular Army , Army Reserve , and Army National Guard . As a result of renewed emphasis on special operations in the 1980s , the Special Forces Branch was established as a basic branch of the Army effective April 9 , 1987 , by General Orders No . 35 , 19 June 1987 . Special branches . Army Medical Department , 27 July 1775 . The Army Medical Department and the Medical Corps trace their origins to 27 July 1775 , when the Continental Congress established the Army hospital headed by a " Director General and Chief Physician . " Congress provided a medical organization of the Army only in time of war or emergency until 1818 , which marked the inception of a permanent and continuous Medical Department . The Army Nurse Corps dates from 1901 , the Dental Corps from 1911 , the Veterinary Corps from 1916 , the Medical Service Corps from 1917 , and the Army Medical Specialist Corps from 1947 . The Army Organization Act of 1950 renamed the Medical Department as the Army Medical Service . On 4 June 1968 , the Army Medical Service was redesignated the Army Medical Department . Chaplains , 29 July 1775 . The legal origin of the Chaplains is found in a resolution of the Continental Congress , adopted 29 July 1775 , which made provision for the pay of chaplains . The Office of the Chief of Chaplains was created by the National Defense Act of 1920 . Judge Advocate General ' s Corps , 29 July 1775 . The Office of Judge Advocate of the Army may be deemed to have been created on 29 July 1775 , and has generally paralleled the origin and development of the American system of military justice . The Judge Advocate General ' s Department , by that name , was established in 1884 . Its present designation as a corps was enacted in 1948 . Civil Affairs , 17 August 1955 . The Civil Affairs / Military Government Branch in the Army Reserve Branch was established on 17 August 1955 . Subsequently redesignated the Civil Affairs Branch on 2 October 1959 , it has continued its mission to provide guidance to commanders in a broad spectrum of activities ranging from host - guest relationships to the assumption of executive , legislative , and judicial processes in occupied or liberated areas .