The River Isen (or Angren in Sindarin) began in the southern Misty Mountains, first flowing south through the fortress of Isengard (or Angrenost) to the White Mountains, where it abruptly bent west and flowed to the sea of Belegaer, the Great Sea.
Its length is about 430 Númenórean miles, making it the eighth-longest known river of Middle-earth.
Isen means Iron (cf. German eisen and Old English isærn = iron), Isengard meaning Iron fortress.
The Isen and Adorn formed the boundary of the Kingdom of Rohan, but the triangle of land between Isen, Adorn, and the White Mountains was a contested land, claimed by the Rohirrim as well as the Dunlendings.
The Isen formed a natural boundary in the Gap of Rohan, and was only crossable at Isengard or at the Fords of Isen, where the Rohirrim fought a number of great battles against the Dunlendings and Saruman's Orcs in the late Third Age.
The second crossing of the Isen is the bridge leading to Blackmarch Fort. This is the only known bridge to cross the river.
As it heads south, the river comes into contact with its first still-standing trees, Saruman's orcs having decimated the rest of the vale's greenery.
The Isen then becomes impassably deep as it falls into the gorge lining the north side of the White Mountains.
The river also marks the northern border of Gondor, though Gondorian holdings, such as this tower, have long been abandoned this far north.
|Settlements, Areas and Landmarks of Gap of Rohan
|Areas:||Wulf's Cleft • Isendale • Heathfells|
|Settlements:||Grimbold's Camp • Forthbrond|
|Landmarks:||Âthdâr • Brôntrig • Cuvnerth • Dol Baran • The Pit of Iron • River-watch • The River Isen • Slave Stockades • The Smelters • The Sprawling Dark • The Underworkings|