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What Is the Longest US War?

As of early 2012, the United States had been officially involved in the War in Afghanistan for more than 10 years, making it the longest US war. The United States military's involvement in the Iraq War made it the second-longest US war at eight years and nine months — four months longer than the country's official involvement in the Vietnam War. If combined, the time the United States was involved in the War in Afghanistan and the Iraq War was three years longer than its involvement in World War I, World War II, the Korean War and the Vietnam War combined.

More facts about the United States and wars:

  • The United States has been officially involved in about 12 major wars in 235 years. Spread evenly, that's about one war every 20 years.

  • The longest war in history is thought to be the Three Hundred and Thirty-Five Years' War between the Netherlands and the Isles of Scilly. Though there were never any shots fired, and there wasn't strictly an official declaration of war to begin with, both parties officially declared peace in 1986. On the other end of the spectrum is the Anglo-Zanzibar War, which started on 27 August 1896 and lasted all of 38 minutes before the Zanzibaris surrendered.

  • Although the War in Afghanistan and the Iraq War have been the longest US wars, they have been far from the deadliest. The deadliest war in terms of US military deaths was the US Civil War, with about 625,000 deaths. That was more than 95 times the American military deaths of the War in Afghanistan and the Iraq War combined as of early 2012.

Discussion Comments

By anon1007396 — On Jun 30, 2022

The Iraq war wasn't deadly? 288,000 deaths according to the Iraq body count. CBO estimated that it costs US taxpayers $2.4 trillion. We could have ended all hunger and eradicated all the student debt in the USA for less than that.

By anon1003821 — On Sep 11, 2020

Vietnam was the longest war the USA was involved in at 30 years.

By anon1000766 — On Dec 21, 2018

The Korean war technically hasn't ended. There was an armistice signed, but no treaty. That would make it the longest running war the U.S. has participated in; however, there hasn't been any real military activity since the armistice was signed in 1953, so most people don't consider us to still be at war. The Vietnam war also is longer running, starting in 1955 and running until 1975. If troops are pulled out of Afghanistan before 2021, Vietnam will remain the longest war in U.S. history. In addition, while the casualties in the Vietnam war aren't nearly that of the civil war or the world wars; they are 10 times that of the war in Afghanistan.

By anon328644 — On Apr 04, 2013

The Civil War was the war with more American casualties, but what about the bloodiest American battle? I can answer that. It was on June 5-6 at Normandy in France when the Allies invaded Hitler's Atlantic wall.

By malik23 — On Jul 23, 2012

I did not know that the Afghanistan War was the United States' longest war.

By anon255486 — On Mar 17, 2012

What about the Gulf war?

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