Great Britain began stopping American sea vessels and forcing subjects on the vessels into the British military. This practice was called "impressment." This was the main cause of the war.
You're gonna work for us whether you like it or not!
By late 1811 the so-called “War Hawks” in Congress were putting more and more pressure on Madison, and on June 18, 1812, the president signed a declaration of war against Britain. Though Congress ultimately voted for war, both House and Senate were bitterly divided on the issue.
The war began with an attack on Canada, both as an effort to gain land and to cut off British supply lines to Tecumseh's Indian confederation, which had long troubled the US. The initial battles in Canada were not as easy as the War Hawks hoped, and the inexperienced American soldiers were pushed back rapidly.
In the Belgian city of Ghent, American negotiators (including John Quincy Adams and Henry Clay) met with British diplomats. After considerable bickering, the negotiators signed the Treaty of Ghent on December 24, 1814, officially ending the war. The treaty returned US-Britain relations to the same status as they had been before the war. The US neither gained nor lost any territory.
Results of the War of 1812 between Great Britain and the United States, 1812-1815, involved with no geographical changes. The main result of the war was two centuries of peace between the United States and Britain.
One more result that resulted from the war was the U.S's manufacturers getting more active and increasing skill because of the abrupt stop of trade.