Many of these new settlers were sent into the area by the British from Canada in an effort to establish their dominance over the Great Lakes. In 1783, control of The Thumb was officially transferred to the newly formed United States, after the American Revolution and by the Treaty of Paris. The British were a dominant influence until after the War of 1812, when the northern border was firmly defined and this area came under US control. The US organized the Northwest Territory, and American settlement of Michigan and The Thumb was well underway by the mid-19th century. Construction of the Erie Canal through Central New York created stronger connections with the port of New York and eastern markets. Settlers migrated west from New York and New England into Ohio and Michigan, seeking new territory.