Origins The Continental Army was created on 14 June 1775 by the
Second Continental Congress as a unified army for the colonies to fight
Great Britain, with
George Washington appointed as its commander. The army was initially led by men who had served in the
British Army or colonial militias and who brought much of British military heritage with them. As the Revolutionary War progressed,
French aid, resources, and military thinking helped shape the new army. A number of European soldiers came on their own to help, such as
Friedrich Wilhelm von Steuben, who taught
Prussian Army tactics and organizational skills. during the
American Revolutionary War, as depicted in a
watercolor painting by
H. Charles McBarron Jr. (1902–1992) prompted Great Britain's government to begin negotiations, resulting in the
Treaty of Paris and Great Britain's recognition of the United States as an independent state. The Army fought numerous pitched battles, and sometimes used
Fabian strategy and
hit-and-run tactics in the South in 1780 and 1781; under Major General
Nathanael Greene, it hit where the British were weakest to wear down their forces. Washington led victories against the British at
Trenton and
Princeton, but lost a series of battles in the
New York and New Jersey campaign in 1776 and the
Philadelphia campaign in 1777. With a decisive victory at
Yorktown and the help of the French, the Continental Army prevailed against the British. After the war, the Continental Army was quickly given land certificates and disbanded in a reflection of the
republican distrust of standing armies.
State militias became the new nation's sole ground army, except
a regiment to guard the
Western Frontier and one battery of
artillery guarding
West Point's arsenal. However, because of continuing conflict with
Native Americans, it was soon considered necessary to field a trained standing army. The
Regular Army was at first very small and after General
St. Clair's defeat at the Battle of the Wabash, where more than 800 soldiers were killed, the Regular Army was reorganized as the
Legion of the United States, established in 1791 and renamed the United States Army in 1796. In 1798, during the
Quasi-War with France, the
U.S. Congress established a three-year "
Provisional Army" of 10,000 men, consisting of twelve
regiments of
infantry and six troops of light
dragoons. In March 1799, Congress created an "Eventual Army" of 30,000 men, including three regiments of
cavalry. Both "armies" existed only on paper, but equipment for 3,000 men and horses was procured and stored.
19th century standing on the parapet of his makeshift defenses as his troops repulse attacking
Highlanders during the
defense of New Orleans, the final major and most one-sided battle of the
War of 1812, mainly fought by militia and volunteers.
War of 1812 The War of 1812 was the second and last war between the United States and Great Britain. The war was split between a Northern, Southern, and naval campaign. While a large part of the war was fought between the United States and Great Britain, there were a variety of native tribes that fought on both sides of the conflict. The result of the war is the
Treaty of Ghent and is generally considered to be inconclusive, and brought upon a period of peace between the United States and Great Britain that has lasted for over two centuries.
Seminole Wars There was a long period of war between the United States and the
Seminoles that lasted over 50 years. The usual strategies utilized against Native American tribes were to seize winter food supplies and to form alliances with enemies of a tribe. These were not viable options against the Seminoles, largely due to the fact of lack of climate variability in Florida and because of the long history of warring between the Seminole tribe and other tribes in the Florida region.
Mexican–American War The U.S. Army fought and won the Mexican–American War, which was a defining event for both countries. The U.S. victory resulted in the
Treaty of Guadalupe Hidalgo, in which Mexico
ceded a large portion of land to the United States which included the modern-day states of
California,
Nevada,
New Mexico,
Arizona,
Texas, and parts of
Colorado and
Wyoming.
American Civil War , the turning point of the American Civil War The
American Civil War was the costliest war for the U.S. in terms of casualties. After most
slave states, located in the southern U.S., formed the
Confederate States, the
Confederate States Army, led by former U.S. Army officers, mobilized a large fraction of Southern white manpower. Forces of the United States (the "Union" or "the North") formed the
Union Army, consisting of a small body of regular army units and a large body of volunteer units raised from every state, north and south, except
South Carolina. For the first two years, Confederate forces did well in set battles but lost control of the border states. The Confederates had the advantage of defending a large territory in an area where disease caused twice as many deaths as combat. The Union pursued a strategy of seizing the coastline, blockading the ports, and taking control of the river systems. By 1863, the Confederacy was being strangled. Its eastern armies fought well, but the western armies were defeated one after another until the Union forces captured New Orleans in 1862 along with the Tennessee River. In the
Vicksburg Campaign of 1862–1863, General
Ulysses Grant seized the
Mississippi River and cut off the Southwest. Grant took command of Union forces in 1864 and after a series of battles with very heavy casualties, he had General
Robert E. Lee under siege in Richmond as General
William T. Sherman captured Atlanta and
marched through Georgia and
the Carolinas. The Confederate capital was abandoned in April 1865 and Lee subsequently surrendered his army at Appomattox Court House. All other Confederate armies surrendered within a few months. The war remains the deadliest conflict in U.S. history, resulting in the deaths of 620,000 men on both sides. Based on 1860 census figures, 8% of all white males aged 13 to 43 died in the war, including 6.4% in
the North and 18% in
the South.
Later 19th century Following the Civil War, the U.S. Army had the mission of containing western tribes of Native Americans on the
Indian reservations. They set up many forts, and engaged in the last of the
American Indian Wars. U.S. Army troops also occupied several Southern states during the
Reconstruction Era to protect
freedmen. The key battles of the
Spanish–American War of 1898 were fought by the Navy. Using mostly
new volunteers, the U.S. forces defeated
Spain in land campaigns in
Cuba and played the central role in the
Philippine–American War.
20th century Starting in 1910, the army began acquiring
fixed-wing aircraft. In 1910, during the
Mexican Revolution, the army was deployed to U.S. towns near the border to ensure the safety of lives and property. In 1916,
Pancho Villa, a major rebel leader, attacked
Columbus, New Mexico, prompting a
U.S. intervention in Mexico until 7 February 1917. They fought the rebels and the Mexican federal troops until 1918.
World Wars , The
United States joined World War I as an "Associated Power" in 1917 on the side of
Britain,
France,
Russia,
Italy and the other
Allies. U.S. troops were sent to the
Western Front and were involved in the last offensives that ended the war. With the armistice in November 1918, the army once again decreased its forces. In 1939, estimates of the Army's strength ranged between 174,000 and 200,000 soldiers, smaller than that of
Portugal's, which ranked it 17th or 19th in the world in size. General
George C. Marshall became Army chief of staff in September 1939 and set about expanding and modernizing the Army in preparation for war. The United States joined
World War II in December 1941 after the
Japanese attack on Pearl Harbor. Some 11 million Americans were to serve in various Army operations. On the
European front, U.S. Army troops formed a significant portion of the forces that landed in French North Africa and
took Tunisia and then
moved on to Sicily and later
fought in Italy. In the June 1944
landings in northern France and in the subsequent
liberation of Europe and defeat of
Nazi Germany, millions of U.S. Army troops played a central role. In 1947, the number of soldiers in the US Army had decreased from eight million in 1945 to 684,000 soldiers and the total number of active divisions had dropped from 89 to 12. The leaders of the Army saw this demobilization as a success. In the
Pacific War, U.S. Army Soldiers made up the vast majority of ground forces there, capturing the
Pacific Islands from Japanese control. In total, there were 86 amphibious landings throughout the Pacific. The Army conducted 71. Following the
Axis surrenders in May (Germany) and August (Japan) of 1945, Army troops were deployed to Japan and Germany to occupy the two defeated nations. Two years after World War II, the
Army Air Forces separated from the Army to become the
United States Air Force in September 1947. In 1948, the Army was
desegregated by
order 9981 of President
Harry S. Truman.
Cold War 1945–1960 at the
Nevada Test Site during the
Korean War|alt= The end of World War II set the stage for the East–West confrontation known as the
Cold War. With the outbreak of the
Korean War, concerns over the defense of Western Europe rose. Two corps,
V and
VII, were reactivated under
Seventh United States Army in 1950 and U.S. strength in Europe rose from one division to four. Hundreds of thousands of U.S. troops remained stationed in West Germany, with others in
Belgium, the
Netherlands and the
United Kingdom, until the 1990s in anticipation of a possible
Soviet attack. , 1961 During the Cold War, U.S. troops and their allies fought
communist forces in Korea and
Vietnam. The Korean War began in June 1950, when the Soviets walked out of a UN Security Council meeting, removing their possible veto. Under a
United Nations umbrella, hundreds of thousands of U.S. troops fought to prevent the takeover of
South Korea by
North Korea and later to invade the northern nation. After repeated advances and retreats by both sides and the Chinese
People's Volunteer Army's entry into the war, the
Korean Armistice Agreement returned the peninsula to the status quo in July 1953.
1960–1970 The
Vietnam War is often regarded as a low point for the U.S. Army due to the use of
drafted personnel, the unpopularity of the war with the U.S. public and frustrating restrictions placed on the military by U.S. political leaders. While U.S. forces had been stationed in
South Vietnam since 1959, in intelligence and advising/training roles, they were not deployed in large numbers until 1965, after the
Gulf of Tonkin Incident. U.S. forces effectively established and maintained control of the "traditional" battlefield, but they struggled to counter the
guerrilla hit and run tactics of the communist
Viet Cong and the
People's Army of Vietnam (NVA). position at Dak To, South Vietnam during
Operation Hawthorne During the 1960s, the Department of Defense continued to scrutinize the reserve forces and to question the number of divisions and brigades as well as the redundancy of maintaining two reserve components, the
Army National Guard and the
Army Reserve. In 1967, Secretary of Defense
Robert McNamara decided that 15 combat divisions in the Army National Guard were unnecessary and cut the number to eight divisions (one mechanized infantry, two armored, and five infantry), but increased the number of brigades from seven to 18 (one airborne, one armored, two mechanized infantry and 14 infantry). The loss of the divisions did not sit well with the states. Their objections included the inadequate maneuver element mix for those that remained and the end to the practice of rotating divisional commands among the states that supported them. Under the proposal, the remaining division commanders were to reside in the state of the division base. However, no reduction in total Army National Guard strength was to take place, which convinced the governors to accept the plan. The states reorganized their forces accordingly between 1 December 1967 and 1 May 1968.
1970–1990 during
Operation Just Cause The Total Force Policy was adopted by Chief of Staff of the Army General
Creighton Abrams in the aftermath of the Vietnam War and involved treating the three components of the army – the
Regular Army, the
Army National Guard and the
Army Reserve as a single force. General Abrams' intertwining of the three components of the army effectively made extended operations impossible without the involvement of both the Army National Guard and Army Reserve in a predominantly combat support role. The army converted to an all-volunteer force with greater emphasis on training to specific performance standards driven by the reforms of General
William E. DePuy, the first commander of
United States Army Training and Doctrine Command. Following the Camp David Accords that was signed by Egypt, Israel that was brokered by president
Jimmy Carter in 1978, as part of the agreement, both the United States and
Egypt agreed that there would be a joint military training led by both countries that would usually take place every 2 years, that exercise is known as
Exercise Bright Star. The 1980s was mostly a decade of reorganization. The
Goldwater–Nichols Act of 1986 created
unified combatant commands bringing the army together with the other four
military services under unified, geographically organized command structures. The army also played a role in the invasions of
Grenada in 1983 (
Operation Urgent Fury) and
Panama in 1989 (
Operation Just Cause). By 1989,
Germany was nearing reunification and the Cold War was coming to a close. Army leadership reacted by starting to plan for a reduction in strength. By November 1989 Pentagon briefers were laying out plans to reduce army end strength by 23%, from 750,000 to 580,000. A number of incentives such as early retirement were used.
1990s tanks moving out before the
Battle of Al Busayyah during the
Gulf War In 1990,
Iraq invaded its smaller neighbor,
Kuwait, and U.S. land forces quickly deployed to assure the protection of
Saudi Arabia. In January 1991
Operation Desert Storm commenced, a U.S.-led coalition which deployed over 500,000 troops, the bulk of them from U.S. Army formations, to
drive out Iraqi forces. The campaign ended in total victory, as Western coalition forces routed the
Iraqi Army. Some of the largest tank battles in history were fought during the Gulf war. The
Battle of Medina Ridge,
Battle of Norfolk and the
Battle of 73 Easting were tank battles of historical significance. during the Gulf War, February 1991 After Operation Desert Storm, the army did not see major combat operations for the remainder of the 1990s but did participate in a number of peacekeeping activities. In 1990 the Department of Defense issued guidance for "rebalancing" after a review of the Total Force Policy, but in 2004,
USAF Air War College scholars concluded the guidance would reverse the Total Force Policy which is an "essential ingredient to the successful application of military force".
21st century , Afghanistan On 11 September 2001, 53 Army civilians (47 employees and six contractors) and 22 soldiers were among the 125 victims killed in
the Pentagon in a
terrorist attack when
American Airlines Flight 77 commandeered by five
Al-Qaeda hijackers slammed into the western side of the building, as part of the
September 11 attacks. In response to the 11 September attacks and as part of the global
war on terror, U.S. and
NATO forces
invaded Afghanistan in October 2001, displacing the
Taliban government. The US Army were the first into Afghanistan, with the 10th Mountain Division being the first conventional unit to arrive in country in 2001. The U.S. Army also led the combined U.S. and allied
invasion of Iraq in 2003; it served as the primary source for ground forces with its ability to sustain short and long-term deployment operations. Like Afghanistan, the US Army was the first into Iraq. In the following years, the mission changed from conflict between regular militaries to
counterinsurgency, resulting in the deaths of more than 4,000 U.S. service members (as of March 2008) and injuries to thousands more. 23,813 insurgents were killed in Iraq between 2003 and 2011. take cover during an ambush by enemy forces in Kunar province, Afghanistan, 2009 ,
101st Airborne Division returning fire during a firefight with Taliban forces in Barawala Kalay Valley in
Kunar province, Afghanistan, March 2011 Until 2009, the Army's chief modernization plan, its most ambitious since World War II, was the
Future Combat Systems program. In 2009, many systems were canceled, and the remaining were swept into the
BCT modernization program. By 2017, the Brigade Modernization project was completed and its headquarters, the Brigade Modernization Command, was renamed the Joint Modernization Command, or JMC. In response to
Budget sequestration in 2013, Army plans were to shrink to 1940 levels, although actual Active-Army end-strengths were projected to fall to some 450,000 troops by the end of FY2017. From 2016 to 2017, the Army retired hundreds of
OH-58 Kiowa Warrior observation helicopters, while retaining its Apache gunships. The 2015 expenditure for Army research, development and acquisition changed from $32 billion projected in 2012 for FY15 to $21 billion for FY15 expected in 2014. The US Army saw extensive combat throughout both Afghanistan and Iraq. The
10th Mountain Division was the most deployed unit in the US military during the
Global War on Terror. In the
2026 Iran war, the Army participated via offensive missile launches, air defense operations, and possibly
combat search and rescue. Army forces launched both
ATACMS ==Organization==