Despite the presence of the Baltimore-Washington area, 301 remained the exclusive area code for Maryland until Baltimore and the Eastern Shore were split off as area code 410 on October 6,1991.
301 remained the exclusive area code for Maryland until Baltimore. This was despite the presence of the Baltimore-Washington area. The Eastern Shore were split off as area code 410 on October 6,1991. This was despite the presence of the Baltimore-Washington area.