History

Longest Wars in History

Wars with the longest duration in recorded history.

7 rows8 columns1 views0 downloadsSource: WikipediaUpdated: 2/22/2026
warshistorydurationconflicts
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Combatants
Historical conflict
Period of de facto conflict
De jure peace
De facto duration, years
De jure duration, years
De facto – de jure difference, years
Status of claim
Isles of Scilly vs Dutch RepublicFirst Anglo-Dutch War (Three Hundred and Thirty Five Years' War)1651–16541,9864335329The Dutch Republic under Maarten Tromp declared war solely on the Isles of Scilly, as the final stronghold of the Royalist naval force which was capturing Dutch merchant ships. When the Dutch and the Commonwealth of England signed the Treaty of Westminster (1654), this separate state of war was not mentioned and thus not included in the peace. The Dutch ambassador, visiting in April 1986 to conclude peace, joked that it must have been harrowing to the Scillonians "to know we could have attacked at any moment."
Huéscar vs DenmarkPeninsular War1809–18141,9816172167The Spanish town of Huéscar declared war on Denmark, as a result of the Napoleonic wars over Spain, where Denmark supported the French Empire. The official declaration of war was forgotten until it was discovered by a local historian in 1981, followed by the signing of a peace treaty on 11 November 1981 by the city mayor and the Ambassador of Denmark. Not a single shot was fired during the 172 years of war, and nobody was killed or injured.
Montenegro vs JapanRusso-Japanese War1904–19052,0062102101Montenegro declared war in support of Russia but Montenegro lacked a navy or any other means to engage Japan. After Montenegro (independent in 1904, but united with Serbia by 1918) had voted in 2006 to resume its independence, it concluded a separate peace treaty in order to establish diplomatic relations with Japan. See Japan–Montenegro relations.
Costa Rica vs GermanyWorld War I19181,94512827Due to a dispute over the legitimacy of the government of Federico Tinoco Granados, Costa Rica was not a party to the Treaty of Versailles and did not unilaterally end the state of war. The technical state of war ended after World War II only after they were included in the Potsdam Agreement. Costa Rica did not issue a declaration of war against Germany in World War II.
Soviet Union vs JapanSoviet–Japanese War(Part of World War II)19451,95611110The Soviet–Japanese War was a short conflict that lasted less than a month in 1945. However, despite this, the Soviets refused to sign the Treaty of San Francisco and did not unilaterally end the state of war. Ultimately, the state of war was not formally ended until the Soviet–Japanese Joint Declaration of 1956, 11 years later.
Poland vs JapanWorld War II1941–19451,95741612In December 1941, the Polish government-in-exile unilaterally declared war on Japan. However, as Soviet-occupied Poland refused to sign the Treaty of San Francisco, the country also did not unilaterally end the state of war. Ultimately, the state of war was not formally ended until 1957, when Japan concluded a separate peace treaty in order to establish diplomatic relations with the Polish People's Republic. See Japan–Poland relations.
UN Forces (led by United States) vs IraqGulf War19912,00311312The UN resolution which ended the first Gulf War only enacted a ceasefire. It did not end the state of war with Iraq. The British Government would, 12 years later, use the de jure state of war with Iraq to provide the legal basis for the 2003 invasion of Iraq. Opponents of the Iraq War have criticised this interpretation, with one source labelling it as "legal gymnastics" (see Legality of the Iraq War).
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