Maryland's Patapsco River State Park stretches for 32 scenic and historic miles south and west of Baltimore. Our hike today will take us through the park's Orange Grove section, featuring the remains of once-bustling mill towns serving ironworks, flour mills and other industrial enterprises. Total length of our easy hike should be about 5 miles, mostly on well-shaded trails with a few stream crossings, one picturesque waterfall, and several hundred feet of elevation gain scattered along the way. Bring plenty of beverages, lunch, sunscreen, bug spray, a towel and water shoes (if you'd like to cool off your feet) and about $12 for transportation, admission and trip fees. Meet either at 9 a.m. by the station attendant's kiosk inside the Greenbelt Metro Station or at 9:45 at the Cascade Falls parking lot, the last lot on the left inside the park's Avalon entrance near Elkridge, MD.