The
Kapuas River (or
Kapueas River) is a river in the
Indonesian part of
Borneo island, at the geographic center of
Maritime Southeast Asia. At in length, it is the longest river of Indonesia and one of the world's longest island rivers. It originates in the Müller mountain range at the center of the island and flows west into the
South China Sea creating an extended marshy delta. The delta is located west-southwest of
Pontianak, the capital of
West Kalimantan province. This Kapuas River should be distinguished from another
Kapuas River, which starts on the other side of the same mountain range in central Borneo, but flows to the south, merging with the
Barito River and discharging into the
Java Sea.