Departing the Boston area on August 8, the battery first served garrison duty near Baltimore and in operations in eastern Maryland. In February 1862, it was assigned to the Department of the Gulf under Major General Benjamin F. Butler and shipped for Louisiana on April 19. The regiment saw combat during the early stages of the Siege of Vicksburg, and suffered badly from disease and general debility during the operations. After Maj. Gen. Nathaniel P. Banks took command of the Department of the Gulf, the battery participated in the Siege of Port Hudson, Louisiana. They also saw action during the Second Bayou Teche Campaign in western Louisiana and the Red River Campaign, during which their guns were captured at the Battle of Sabine Crossroads. They were resupplied with new guns in May 1864.