The  lake is the largest lake in the southern part of Trøndelag county. Selbusjø is part of the Nea-Nidelv watershed, with the Nea River flowing into it on the eastern end and the Nidelva River flowing out the western end.
The lake is the largest in southern Trøndelag county. Selbusjø is part of the Nea-Nidelv drainage system, where the Nea River meets it on the eastern side and the Nidelva River exits from the western side.