A number of things though caused the War of 1812
1) Violations of the American Sovereignty by Great Britain..
a) Impressments Imprisonment or kidnapping of U.S. citizens and merchant marines on the open sea
b) Interference with American shipping and trade
c) Britain's refusal to turn over western forts promised to them at the end of the American Revolution, thus supporting the Native-American resistance.
2) American expansionism. Conquering of Great Britain's Canadian colonies to get them off of North America for good.
3) Growing Presence in U.S. politics of War Hawks
a) War Hawks led by Henry Clay
b) Asked for a declaration of war against Great Britain as a response to the grievances listed above and for the chance to take over the British Canadian colonies.
There were four theatres of operation during the war.
1) The Atlantic Ocean
2) The Great Lakes and the Canadian frontier
3) The coast of the United States
4) The Southern states
With the British ships outnumbering the United States vessels, the goal of the British was to protect their own merchant ships to and from Canada while cutting off the American supply line, thus interrupting the U.S. trade and economy. Although there were numerous battles over the two plus years of war, there were six strategic wars in these theatres of operation.
1) British Navy blockades the American Coast by 1813.
Although the American Navy was outnumbered and not as highly trained, they had early success in capturing a number of British frigates. With that, the British sent more ships and tightened the blockade by June 1813, in fact it was so tight that the British were able to land troops on American soil