[2] The parkland comprises 298 non-contiguous acres along the river (travelling downstream) in Berkeley Heights, New Providence, and Summit.
The Parkway was conceived in the 1920s when the county park system was being developed, following the design of the Olmsted Brothers, sons of landscape architect Frederick Law Olmsted.
[2] The Passaic River Parkway lies in the valley of the Passaic River (the drainage basin of Second Watchung Mountain) in northwestern Union County, where the river creates the borders with Somerset and Morris Counties.
There are also parks and nature areas in the riparian floodplain across the river in Watchung, Warren Township, Long Hill Township and Chatham.
[4] The Great Swamp National Wildlife Refuge is just west of the river.