The Blackwater River is a river in the Forest. It starts in the High Mountains, near the Sacred Grove, and from there runs further through the Deep Forest until it forms Lake Blackwater. It then runs trough the Jaws of the Deep Forest and passes the Burnt Hill. It flows through the Hills and then through the Open Forest, where it joins with the Widewater and forms the Moose River. It then flows into the Sea.
It is considered one of the most important ways into the Deep Forest.
During Oath Breaker the Deep Forest Clans camped by the black water river.