The Fly (named after a British naval ship) is the longest river of the island of New Guinea. It rises in the Star Mountains, and crosses the southwestern lowlands before reaching the Gulf of Papua in a large estuary. The Fly has a length of 1050 km; it flows through Papua New Guinea except for a small stretch where it forms the boundary between Papua New Guinea and Indonesia.

The principal tributaries of the Fly are the Strickland and the Ok Tedi which is the site of a major Copper and Gold mine that is causing major pollution in the river system. The Ok Tedi is a river in Papua New Guinea. ...