American Wars Timeline: Major Wars Involving the US

The United States of America has been involved in many wars since the nation was first established. Review this American wars timeline to get a sense of what wars the country has been embroiled in, from its early days to modern times.

american soldiers holding U.S. flag american soldiers holding U.S. flag

18th and 19th Century American Wars Timeline

The American wars timeline of the 18th and 19th centuries starts with the colonies' fight to win independence from Britain and ends with gaining territories from Spain. The United States was involved in five major wars throughout the 18th and 19th centuries.

American Revolution (1775-1783)

Sometimes referred to as the Revolutionary War or the War of American Independence, the struggle most commonly known as the American Revolution led to the establishment of the United States of America as a country. The United States declared its independence from Britain in 1776, though the war waged on until 1783. That year, the Treaty of Paris of 1783 was signed, in which England officially recognized the independence of the 13 American colonies which, over time, grew to 50 states.

War of 1812 (1812-1815)

The War of 1812 was also fought against England. It is sometimes referred to as the Second War of American Independence. This war came about because England was interfering with America's ability to trade with France. Long at war with France, England began insisting that U.S. trade interests stop at British ports and pay a fee before advancing to France.

Unhappy with this, as well as with the fact that American political leaders believed that winning a war against England could lead to America being able to annex Canada (which was then a British territory), the U.S. declared war on England. The war was ended with the signing of the Treaty of Ghent, with neither country gaining anything.

Mexican-American War (1846-1848)

In 1845, the Republic of Texas was annexed into the United States of America. The Mexican government refused to accept this annexation, leading them to launch an attack against American troops. As a result, the U.S. declared war on Mexico. The U.S. prevailed in the Mexican-American War, which ended with the signing of the Treaty of Guadalupe Hidalgo in 1848.

As a result of this war, the United States gained control of areas that later became the states of California, Nevada and Utah. America also gained land that became part of several other western states, including Arizona, Colorado, New Mexico, and Wyoming.


Civil War (1861-1865)

Often described as the War Between the States, the Civil War was fought between the southern states and the northern states. This war occurred because the southern states disagreed with the plans of Abraham Lincoln and the federal government to halt the expansion of slavery. These states seceded from the Union and became the Confederacy.

The war was fought between Confederate states and Union states, with the Union prevailing. Confederate forces surrendered after spending four years fighting the most deadly war the nation had ever experienced to that point. The practice of slavery was ended following the Civil War.

Spanish-American War (1898)

Displeased that the United States viewed Cuba's desire for independence from Spain in a positive light, Spain declared war on America. The U.S. prevailed in the Spanish-American War. It effectively put an end to the influence of Spanish colonial rule throughout the Americas. The war ended with the signing of the Treaty of Paris of 1898. As a result of this war, Spain surrendered Guam, the Philippines and Puerto Rico to the United States.

20th Century Timeline of American Wars

The United States was involved in five major wars during the 20th century. Early in the century, the U.S. got involved in World War I; the first Gulf War (in the Persian Gulf region of the Middle East) was the last major war of the 20th century.

World War I (1914-1918)

World War I began in 1914, but the U.S. didn't formally enter the war until 1917. In 1917, Congress declared war on Germany at the urging of President Woodrow Wilson. This was triggered at least in part by Germany's failure to abide by its agreement to stop submarine warfare in the Mediterranean and the North Atlantic. Germany had also been trying to convince Mexico to join with them in solidarity against the United States.

The U.S. became part of the Allied Powers, which included Britain, France, Japan, and Russia. The Allied Powers were victorious over the Central Forces, which included Austria, Bulgaria, Germany, Hungary, and the Ottoman Empire. The 1918 signing of the Treaty of Versailles marked the end of World War I.


World War II (1939-1945)

World War II started in 1939, but the U.S. didn't officially get involved until 1941. Japan's attack on Pearl Harbor led to the U.S. entering the war. Congress did not delay, declaring war on Japan the day after Pearl Harbor was bombed. Just a few days after the U.S. declaration of war on Japan, Germany declared war on the U.S.

The U.S. became part of the Allied Powers, which also included Britain and the Soviet Union. Germany, Japan and Italy formed the opposing Axis Powers (often referred to as the Axis of Evil). Allied Forces prevailed. The war ended with the creation of the Warsaw Pact and the establishment of the North Atlantic Treaty Organization (NATO).

Korean War (1950-1953)

The Korean War began when the Army of North Korea, a communist country, invaded South Korea. North Korea's goal was to conquer South Korea and join the two nations together as one under joint communist rule. The United States led a United Nations (UN) effort to aid South Korea in its fight against North Korea. The UN forces included troops from a dozen countries. China provided assistance to North Korea.

After the conflict ended in a stalemate, the Korean Demilitarized Zone was put in place to establish a buffer zone between North Korea and South Korea.

Vietnam War (1959-1975)

The Vietnam War was fought between forces representing the communist countries in Southeast Asia, led by North Vietnam, against South Vietnam and other countries in the region that were not under communist rule. The United States was involved from the very beginning, initially providing on-ground training for South Vietnamese forces.

As time went by, the U.S. became more directly involved, via special forces, ground troops and airstrikes. The U.S. used Agent Orange against North Vietnamese forces. The U.S. completed a lengthy withdrawal of forces in 1973, with the war officially ending in 1975. North Vietnam prevailed. After the Vietnam War ended, Laos, Cambodia and South Vietnam became communist states.


Gulf War (1990-1991)

In the Gulf War, dubbed Operation Desert Storm, the U.S. headed up coalition forces authorized by the UN. This coalition included troops from 34 nations working together to accomplish the goal of liberating Kuwait from Iraq. In the summer of 1990, Iraq was able to overtake and occupy Kuwait in just a few hours. After a UN embargo and sanctions were unsuccessful, the next step was military force. The coalition was victorious in their efforts, which involved air and ground forces. Kuwait was liberated though Sadaam Hussein's regime remained in power in Iraq.

21st Century Timeline of American Wars

Though the 21st century has many decades left to go, the U.S. has already been involved in two wars.

War in Afghanistan (2001-2021)

Dubbed Operation Enduring Freedom, the War in Afghanistan began shortly after the 9/11 attacks on the World Trade Center in New York and the Pentagon in Washington, D.C. in 2001. The goal of this military action was to remove Al-Qaeda and Taliban forces from power in Afghanistan. The Taliban quickly retreated and collapsed, but Taliban leader Osama Bin-Laden escaped.

A transitional government was put in power, reconstruction began and major combat operations had ceased by 2003. Forces remained to provide aid and assistance as progress was made. However, widespread insurgency remained. Bin-Laden re-surfaced and was ultimately killed by U.S. Special Forces in 2011. Troop withdrawals were announced soon after, but ten years later, instability remained, as did a significant U.S. military presence. The U.S. government has pledged to withdraw all U.S. forces by September 11, 2021.


Iraq War (2003-2011)

In 2003, the U.S. again led coalition forces against Iraq. This military action was initially named Operation Iraqi Freedom, then renamed Operation New Dawn a year before the end of the conflict. The U.S.-led coalition successfully overthrew the regime of Saddam Hussein, who was killed. Even after that took place, conflict continued with insurgents who were resistant to the establishment of a new government in Iraq. The U.S. started reducing its forces in 2007 and by the end of 2011, all American troops had exited the country. Thus, the war ended in 2011.

Visual American Wars Timeline

To get a clear picture of how the start dates of the major wars America has been involved in unfolded throughout history, review the visual timeline below.

timeline american wars

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Boost Your Military Knowledge

Now that you've reviewed this timeline of the major wars the U.S. has been involved in, you might be interested in learning a bit more about the military. Start by discovering some common military vocabulary words. Then, explore some military slang sayings. This will help you better understand any additional exploration you do in relation to this fascinating topic. From there you can explore other American conflicts like the Cold War.