Separated from Tinicum Island by a backchannel of the Delaware River, Hog Island was used intermittently for agriculture until 1917. The U.S. government comissioned the construction of a shipyard on the swampy patch of land during World War I. The shipyard years began the process of filling in Hog Island's marsh and backchannel to create stabler ground. As a deposit site for material dredged from the Delaware, Hog Island gradually solidified into the Pennsylvania mainland during the mid-twentieth century. Starting in the 1930s, interest grew in the abandoned shipyard as a potential site for an airport. Since opening as the Philadephia Municipal Airport in 1940, the airport has expanded further into Tinicum Township. Indeed, Hog Island cannot be distinguished from Tinicum, itslef no longer an island. The airport has grown to cover about two thirds of Tinicum Township's land, not all of which had been unoccupied like Hog Island.
