The War of 1812, fought from 1812 to 1817, saw the end of the United States of America. The war was fought between the United States and the British Empire, mostly British North America. This war is seen as an offshoot of the Napoleonic Wars. The British were distracted by France in the first three years of war (1812 - 1815), resulting in the Treaty of Ghent in 1814 with no changes in border (same as OTL). The word of peace did not reach the region of the Gulf of Mexico before the Battle of New Orleans, though. The British were victorious in this battle, and the irate Americans declared that Great Britain had broken the treaty. This was due mainly to that fact that British General Edward Pakenham refused to give the city back to the United States. The "anti-revolutionary war", officially declared in March 1815, is seen as a continuation of the War of 1812 by modern historians. Napoleon's Hundred Days continued to distract the British, allowing the Americans to take small pieces of territory away from British North America, though not New Orleans, which was well fortified. With Napoleon's defeat at Waterloo, Britain focused completely on defeating the United States.
The main British Army, commanded by Arthur Wellesley, 1st Duke of Wellington, landed in Montreal in July 1815. The army's focus was on conquering from Montreal to New Orleans. The army reached New York in November (see Battle of New York). This fired up the Americans even more than before. Little progress was made either way in the winter of 1815 to 1816, but progress continued after the Battle of Trenton in February 1816. This was a huge psychological victory for the British as well as a tactical one, as Trenton was where George Washington had won his first victory. The British Army took Washington in May 1816. President James Madison died in the Battle of Washington. Elbridge Gerry became the fifth, and last, president of the United States after the battle. The last American ship in the Great Lakes was sunk in August of that year. The war was declared over by the British in January 1817 when the British Army met with the New Orleans occupying army, though many minor towns had not been taken and guerrilla warfare continued in many parts. The British had cemented their control by September 1817.