On June 9, 1862, the department took part in its only engagement of the war, the Battle of Port Republic, during Jackson's Valley Campaign. Two brigades from the division of James Shields, commanded by Erastus B. Tyler, were outnumbered and defeated by forces led by Stonewall Jackson. The federals lost 1,002 men, while the confederates lost 816. It was Jackson’s costliest battle of the campaign, but was both a tactical and strategic victory for the confederates as it freed Jackson’s army to reinforce Robert E. Lee in the Seven Days Battles.