Located along the Susquehanna River, northwest of HdG, off Route 155. 410-557-7994. The Susquehanna State Park offers excellent fishing opportunities, boating, mountain biking, horseback riding, hiking, bird watching, picnicking, and camping. The children will enjoy the playground, as well. The historic area features the Rock Run Grist Mill, built-in 1794, the New Jersey toll House, and the Archer Museum.