During the War of 1812 where were American troops most successful? The sea. Lake Champlain and Lake Erie. On land
January 8, 1815, final assault on New Orleans was a significant rout of the British forces, by almost any measure.
But when asking "most successful", there are other factors involved, especially in stopping lines of communication. THis especially is true about the battle of Lake Erie, which cutoff the British from going South from Canada.