[2] It is located just to the west of the Bensbach River of Western Province, Papua New Guinea.

The Maro flows from north-east to south-west, into the Arafura Sea.

Associated with the river is a complex system of swamps and oxbow lakes which are of great importance for a large number of birds and reptiles.

The Maro River borders the northern side of Wasur National Park.

The warmest month is September when the average temperature is around 26 °C, and the coldest is May, at 21 °C.