The Fly, at 1,050 kilometres (650 mi), is the second longest river in Papua New Guinea, after the Sepik. By volume of discharge, the Fly is the largest river in Oceania, the largest in the world without a single dam in its catchment, and overall the 25th-largest primary river in the world. It rises in the Victor Emanuel Range arm of the Star Mountains, and crosses the south-western lowlands before flowing into the Gulf of Papua in a large delta.