The majority of the river flows through the Papua New Guinea (PNG) provinces of Sandaun (formerly West Sepik) and East Sepik, with a small section flowing through the Indonesian province of Papua.
Sebagian besar sungai mengalir melalui Papua Nugini (PNG) di Provinsi Sandaun (sebelumnya "West Sepik") dan Provinsi Sepik Timur, serta sebagian kecil mengalir melalui Indonesia di provinsi Papua.