The Patriot's War - Detroiters Get Greedy
Most people think of the United States as having been more or less done with fighting the British by the 1830s. For the Great Lakes region, though, there was still one major war left to fight, an effort to drive the British from North America once and for all, which is known as the Patriot's War. The partisans were organized through secret societies known as Hunters Lodges, and labeled themselves as "Patriots".
In 1837, Patriots living in Michigan and Canada made an attempt to seize the Canadian peninsula containing Windsor and add it to the territory of the United States. In December they used a small steamboat to cross the Detroit River, leading to the "Battle of Windsor", which ended with the Patriots retreating back to the United States. Then in January of 1838, Patriots seized a number of ships from Detroit and attacked the city of Amherstburg. In February, Patriots marched across the ice to Fighting Island, south of Detroit, with the intention of attacking Sandwich, but were driven back to the mainland by British and Canadian forces alerted by American general Hugh Brady. In addition, Detroit-area Patriots attempted to seize Fort Gratiot and the United States Arsenal at Dearborn, and were fended off by Michigan Militia troops.
While the Patriot movement apparently had extensive support all along the US/Canadian border, the War was essentially over by 1838, though the Hunters Lodges remained in existence until President Tyler called upon the public to break ties with the organization in 1841. While brief, the war had significant consequences in the Detroit area. Among other things, it was a major factor in the decision to build Fort Wayne, a major historical landmark currently in great danger of being lost to neglect. On the British side, they built three fortifications on Bois Blanc (known today as Boblo Island) for the same reasons. More generally, the diplomatic actions necessary to quiet down the Patriot movement finally established a political balance between the United States and England, and undoubtedly contributed to Canada gaining home rule a generation later.
Stories and Speculation
It's interesting to consider the "what-if" scenario where the Patriots succeeded in seizing some or all of Canada from England, which would undoubtedly have weakened the British Empire, dramatically altered the political dynamics leading to the Civil War, and given "Manifest Destiny" a whole new direction. Alternately, if the war had grown to a full-scale international conflict all bets are off: how about a Russian western Canada (after all, they originally owned Alaska), and a French-dominated Great Lakes? Even disregarding changes in the outcome of the War, there is still plenty to work with. Among other things, perhaps the "Hunters Lodge" secret societies survived into the modern day; if nothing else, one has to wonder whether the masonic structure of the Lodges may have reflected a connection with Detroit's Freemasons.
Sources
The State of Michigan's Department of Military and Veteran's Affairs has a brief overview of the war, and the History Cooperative provided an exploration of treatment of the conflict by historians (Archive.org link). Finally, the province of Ontario has a variety of Historical Plaques commemorating the war, known there as "the Rebellion of 1837".