The largest and most decisive battle of the War of 1812 was fought after the treaty ending the war had been signed in Europe. News of the Treaty of Ghent concluded on Decenber 24, 1814, had not yet crossed the Atlantic when Gen. Andrew Jackson's mixed force of militia and American regulars defended New Orleans, Louisiana, against a larger British army commanded by Lt. Gen. Edward Pakenham. Jackson won such a stunning victory at New Orleans that the United States was able to claim overall victory in what had been for the Americans an ignominious war, and General Jackson cemented a reputation for military heroism that would help catapult him into the presidency thirteen years later.
When Gen. Andrew Jackson arrived in New Orleans on December 1, 1814, he found that Col. Arthur P. Hayne had done little to prepare the city against an expected British attack. British Admiral Alexander Cochrane had been building up forces in Jamaica as he awaited Pakenham's arrival from Europe with reinforcements. Cochrane's fleet arrived from Jamaica on December 13. The British overtook Lake Borgen and established a post on Pea Island then captured the Jacques Villere plantation on December 23rd establishing a headquarters.
Jackson then ordered the ships The Caroline and The Louisianna to attack the Villere plantation that same night - neither side established clear lines. Pakenham arrived on December 25 and was bombarded by American ships. The Americans then entrenched themselves behind the Rodriguez Canal. On December 28, Pakenham again tried usuccessully to attack the American position. On January 8, British Maj. Gen. Samuel Gibbs pushed against the American left, Jackson's strongest point, only to be destroyed by heavy artillery fire defeating the British. News of the peace treaty soon arrived in North America, and the War of 1812 was over.
taken from - L. Edward Purcell et al., The Encyclopedia of Battles in North America 1517-1916 (New York, NY: Facts on File, Inc., 2000): 192-194.