The Battle of Boonsboro took place on July 8, 1863, in Washington County, Maryland, as part of the Gettysburg Campaign of the American Civil War. The Confederate cavalry, holding the South Mountain passes, fought a rearguard action against elements of the Union 1st and 3rd Cavalry Divisions and infantry. This action was one of a series of cavalry engagements around Boonsboro, Hagerstown, and Williamsport.