Calvert Cliffs State Park (near Solomons, in Calvert County, Md.): This park offers a wide variety of wilderness scenery and trails for moderate-length day hikes. They wind through forests and then descend into a primordial tidal marsh with grasses, waterfowl, and cypress trees. Most hikes include at least one view of the Chesapeake Bay from atop the cliffs or from a small beach at the base of the marsh.
Swallow Falls State Park (Garrett County, Md.): A great place for families to hike in Western Maryland, this park's short trails wind through dark, peaty forest and offer relatively easy access to some stunning scenery. There are overlooks to three waterfalls -- Swallow Falls, Tolliver Falls, and the 63-foot-high cascading Muddy Creek Falls.
Big Savage Trail in Savage River State Forest (Garrett County, Md.): This rugged trail extends 17 miles along the ridge of Big Savage Mountain, passing impressive vistas along the way. A tough hike through almost total wilderness, it's the best choice for serious backpacking in Western Maryland.