Why was that battle fought after the peace treaty was signed?

The Last Battle of the war of 1812. ... Many people think the battle of New Orleans ended the War of 1812, but this is not the case. A peace treaty, the treaty of Ghent had been signed before the battle started, but news of the treaty did not arrive in America until after the battle was fought

Contributing factors  leading  to the harlem renaissance were the great migration of african americans to northern cities, which concentratedambitious  people in places where they could encourage each  other, and the first world war, which had created new industrial work opportunities for tens of thousands of people.