The Appalachian Trail in Maryland passes several historic sites, offers some of the Trail's gentlest terrain, and features several lovely vistas.
Only 41 miles from top to bottom, the A.T. is this state is home to the original Washington Monument and the only war correspondents monument in the United States. There are many good access points for day-hikes to overlooks, with a string of state and county parks along its length offering parking and various amenities. The southernmost three miles follow the historic Chesapeake & Ohio Canal Towpath along the Potomac River--the flattest three miles of the entire A.T. The whole state can be hiked in three to five days. Considered relatively easy by A.T. standards, Maryland is a good place to find out if you're ready for more rugged parts of the Trail.