- Type: River.
- Length: 600 miles.
- Geographic Area: Rhovanion.
The Celduin (S."Running River") rose within the mountain Erebor, passed through the Long Lake (where its waters were joined by the Forest River), was joined further south by the Carnen and other smaller tributaries, and emptied into the distant Sea of Rhûn.
Most trade with the East came along the Celduin, for the Dorwinrim were among the only Easterlings not on hostile terms with the West.
- MERP: Northwestern Middle-earth Campaign Atlas
- MERP: Northwestern Middle-earth Gazetteer