Gaithesburg Salisbury Annapolis Baltimore
Interstate 70 Interstate 68 Interstate 95 Interstate 83
Transpeninsular Line 49th Parallel Mason-Dixon Line Tropic of Cancer
Bay State Old Line State Centennial State Peach State
Chicago Boston New York Washington DC
Putuxent River Potomac River Susquehanna River Patapso River
Herring Bay San Pablo Bay Cape Cod Bay Chesapeake Bay
15.6 million 560 000 5.6 million 1.56 million