Gunpowder Falls State Park (nearly 18,000 acres in Harford and Baltimore Counties) was established to protect the stream valleys of the Big and Little Gunpowder Falls and the Gunpowder River, which begins at Days Cove where the Big and Little Gunpowders converge. A variety of topography exists in this long, narrow park, from tidal marshes and wetlands to steep, rugged slopes.

There are more than 100 miles of trails, including the 21 mile Northern Central Railroad (NCR) Trail. The park features excellent trout fishing opportunities, as well as other freshwater and tidal fishing areas. Park areas include Hereford Area, along York Rd. in Parkton; the NCR Trail which extends from Ashland to the Pennsylvania line; the Central Area which extends from Baldwin to Days Cove along both river valleys and includes the historic village of Jerusalem; the Hammerman Area which is located in Chase near the intersection of Eastern Avenue and Grace Quarters Road and offers a swimming beach on the Gunpowder River; and Dundee Creek Marina, also located in Chase which offers boat launching, rowboat rental, fuel and a marina store.