Upper Bay is a major tidal estuary forming part of the New York/New Jersey Harbor, specifically within Hudson County, New Jersey, and intersecting with Kings County, New York. This expansive saltwater system is a dynamic and productive fishery characterized by brackish waters, significant tidal influence, and a variety of underwater structures. It serves as a critical overwintering habitat for several key fish species and offers diverse angling opportunities from both shore and boat. The area's salinity can vary widely, from nearly fresh to fully marine conditions, influencing the species present throughout the year.