The War of 1812, between the United States of America and the British Empire (particularly Great Britain and British North America), was fought from 1812 to 1815.
There were several immediate stated causes for the U.S. declaration of war: first, a series of trade restrictions introduced by Britain to impede American trade with France, a country with which Britain was at war (the U.S. contested these restrictions as illegal under international law); second, the impressment (forced recruitment) of U.S. citizens into the Royal Navy; third, the British military support for American Indians who were offering armed resistance to the expansion of the American frontier to the Northwest. An unstated but powerful motivation for the Americans was the need to uphold national honor in the face of what they considered to be British insults (such as the Chesapeake affair).
American expansion into the Northwest (Ohio, Indiana, Michigan, Illinois and Wisconsin) was impeded by Indian raids. Some historians maintain that Americans wanted to seize parts of Canada, while others argue this was merely a tactic designed to obtain a bargaining chip. Some members of the British Parliament at the time and dissident American politicians such as John Randolph of Roanoke also claimed that land hunger rather than maritime disputes was the main motivation for the American declaration. Although the British made some concessions before the war on neutral trade, they saw themselves as having the right to reclaim their deserting sailors, and also as the protectors of the native Amerindians from encroaching settlers. The British also had the long-standing goal of creating a large "neutral" Indian state that would cover much of Ohio, Indiana and Michigan. They made the demand as late as 1814 at the peace conference, but lost battles that would have validated their claims.
The war was fought in four theatres: on the oceans, where the warships and privateers of both sides preyed on each other's merchant shipping; along the Atlantic coast of the U.S., which was blockaded with increasing severity by the British, who also mounted large-scale raids in the later stages of the war; on the long frontier, running along the Great Lakes and Saint Lawrence River, which separated the U.S. from Upper and Lower Canada (Ontario and Quebec); and finally along the coast of the Gulf of Mexico, where U.S. General Andrew Jackson defeated the Creek Indians at the Battle of Horseshoe Bend (1814) and a major British regular army at the Battle of New Orleans (early 1815).
During the course of the war, both the Americans and British launched invasions of each other's territory, all of which were unsuccessful or gained only temporary success. At the end of the war, the British held parts of Maine and some outposts in the sparsely populated West while the Americans held Canadian territory near Detroit, but these occupied territories were restored at the end of the war.
In 1813, the Americans gained two of their main goals by breaking a confederation of Native American tribes. By taking control of Lake Erie, they cut them off from British aid, and Tecumseh, the Indian leader, was killed at the Battle of the Thames. While some Natives continued to fight alongside British troops, they subsequently did so only as individual tribes or groups of warriors and where they were directly supplied and armed by British agents.
After two years of warfare, the major causes of the war had disappeared. Neither side had any reason to continue or any chance of gaining a decisive success which would compel their opponents to cede territory or advantageous peace terms. As a result of this stalemate, the two countries signed the Treaty of Ghent on 24 December 1814. News of the peace treaty took two months to reach the U.S., during which fighting continued. In this interim, the Americans won a major victory at the Battle of New Orleans, while the British won the Battle of Fort Bowyer.
In the United States, battles such as New Orleans and the earlier successful defence of Baltimore (which inspired the lyrics of the U.S. national anthem, The Star-Spangled Banner) produced a sense of euphoria over a "second war of independence" against Britain. It ushered in an "Era of Good Feelings," in which the partisan animosity that had once verged on treason practically vanished. Canada also emerged from the war with a heightened sense of national feeling and solidarity. This was later expressed as the "Militia Myth," the notion that locally recruited militia rather than British regular troops bore the major burden of the fighting in Canada and the adjoining parts of the United States. Britain, which had regarded the war as a sideshow to the Napoleonic Wars raging in Europe, was less affected by the fighting; its government and people subsequently welcomed an era of peaceful relations with the United States.