Patapsco Valley State Park

Patapsco Valley State Park, established in 1907 as one of the earliest units in the Maryland park system, follows roughly 32 miles of the Patapsco River across several counties near Ellicott City. The park includes the Thomas Viaduct, an 1835 stone railroad bridge still in active use and among the oldest multi-arch railroad bridges in the country. Several 19th-century mill towns once stood along the river within the park, many destroyed by catastrophic floods, including one in 1868 and another during Hurricane Agnes in 1972. Today the park is divided into several distinct recreation areas connected by trails along the river valley.