The history of the unit as we know it begins after the War of 1812, when 4 infantry regiments, the 2nd, 3rd, 7th, and 44th, were consolidated into the 1st. The 7th and 44th were the regular army regiments which helped General Andrew Jackson win the glorious battle of New Orleans in 1815. Following the war, the 1st Inf. was stationed in the southwest until 1827. In that year the 1st Inf. moved into the old Northwest Territory to garrison forts in Wisconsin, Minnesota, and Illinois.
Here, the regiment took part in the Black Hawk War of 1832. In 1836 it was transferred under Col. Zachary Taylor to Florida until 1841 where it fought in the Seminole War. It was an extremely difficult war of small unit actions and miserable conditions. Rached with illness, the regiment was transferred from Florida back to the northwest in 1841. The years just before the Mexican War found the regiment gradually moving westward with the frontier until 1845 where it was spread from Ft. Snelling in Minnesota, to Ft. Scott in Kansas.