The John Heinz National Wildlife Refuge at Tinicum is a 1000-acre National Wildlife Refuge in Philadelphia and Tinicum Township, Pennsylvania. Adjacent to Philadelphia International Airport, the refuge is designed to the largest remaining freshwater tidal marsh in Pennsylvania. Established in 1972 as the Tinicum National Environmental Center, it was renamed in 1991 after the late H. John Heinz III, who helped preserve Tinicum Marsh.