Company L fought through the remainder of the Peninsula campaign alongside the 1st Minnesota Infantry, retreating following the Union defeat in the Seven Days Battles. The next major engagement for the unit came at the Battle of Antietam on September 17, 1862. A tactical blunder exposed the regiment's flanks at a position known as “the West Woods.” As a result, the opposing Confederates under the command of Thomas “Stonewall” Jackson released a three-sided torrent of fire against the men of Company L. The walls of lead cut down roughly half the men of the company resulting in a casualty list which included four of the eight Northfielders. Following the Confederate withdrawal from Maryland, the 1st Minnesota Infantry played minor roles in the Battles of Fredericksburg and Chancellorsville in the winter of 1862 and the spring of 1863. However, the unit's greatest test would come in General Robert E. Lee’s second invasion of the North, at Gettysburg, Pennsylvania.