18.000 scenic acres in teh Gunpowder River Valley including both Baltimore and Harford Counties. The park features over 100 miles of trails, trout streams, and the historic village of Jerusalem Mill, an 18th century grist mill company town. Other park areas include a multi-use rail trail, swimming beach, picnic area, and marina. Guided trips with local outfitters are available for flat water and moving water kayaking, canoeing, fly-fishing for trout, bass fishing, catamaran sailing, windsurfing