Why did Jackson fight the battle of New Orleans?

Major General Andrew Jackson fought the Battle of New Orleans for a number of reasons. First is that neither the British not Jackson and his men had heard that the two warring sides had already signed a treaty to end the hostilities in Ghent, Belgium on December 24th, 1814. Also, Jackson had been a prisoner of the British during the American Revolution and he was said to still hold a lot of personal animosity towards them for that reason.

Explanation:

Jackson had declared martial law in New Orleans and called on anyone and everyone to try to defend the city from the British incursion. Skirmishes began on Dec 23rd, 1814 and culminated in the Battle of New Orleans on the 8th of January, 1815. The American group of militia fighters and whomever else was prepared to defend the city were able to outwit the British who suffered many casualties despite the upper hand they had in terms of tactics and equipment.