18 Jun 1812: War of 1812 The War of 1812 was a military conflict, lasting for two and a half years, fought by the United States of America against the United Kingdom of Great Britain and Ireland, its North American colonies, and its Native American allies.
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1861
12 Apr 1861—9 Apr 1865: American Civil War The American Civil War, widely known in the United States as simply the Civil War as well as other sectional names, was a civil war fought from 1861 to 1865 to determine the survival of the Union or independence for the Confederacy.