Boundary disputes 1 Gettysburg, Battle of, Gettysburg, Pa., 1863 1 Indians--First contact with Europeans 1 Law offices--Records and correspondence 1 Legal issues 1 Local transit--Pennsylvania--Philadelphia 1 Mason-Dixon Line 1 more ... Mexican War, 1846-1848--Campaigns--Maps 1 Native Americans 1 Pennsylvania--Boundaries 1 Pennsylvania--History--Colonial period, ca. 1600-1775 1 Railroads 1 Railroads--Management 1 Spouses--Correspondence--19th century 1 Topographical surveying--United States 1 Transportation 1 United States. Army of the Potomac 1 United States. Army. Corps of Engineers--History--19th century 1 less ...