Gettysburg, Battle of, Gettysburg, Pa., 1863 1 Mexican War, 1846-1848--Campaigns--Maps 1 Politics and government 1 Spouses--Correspondence--19th century 1 Topographical surveying--United States 1 United States. Army of the Potomac 1 United States. Army. Corps of Engineers--History--19th century 1 more ... less ...