It began in the southern Misty Mountains from Nan Curunir, first running south through the Fortress of Isengard to the White Mountains through the Gap of Rohan, and then bent west finally emptying into the Sea of Belegaer.
According to the The Atlas of Middle-earth, it was around 200 miles in total length from east to west. The Isen also formed a natural boundary in the Gap of Rohan, and was only crossable at Isengard or at the Fords of Isen. Many miles west of the Gap of Rohan, the Isen was joined by its tributary, the river Adorn. The river was apparently not bridged, but it could be crossed at the Fords of Isen about forty miles south of Isengard.
It was also referred to as Sîr Angren.
The Isen and the Adorn formed the western boundary of the Kingdom of Rohan and was treated to be a natural defence against the Dunlendings as well as being watched by the Riders 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.
During the War of the Ring, Saruman diverted the Isen away from Isengard as he turned the fortress into a war factory, and it was dammed at the northern wall. When the Ents attacked Isengard, they broke the dam and restored the original flow of the river, temporarily drowning all of Isengard.
|Nunduinë • Siril|
|Glanduin • Gwathló • Hoarwell • Lune • Sirannon • Withywindle|
|Anduin • Celebrant • Enchanted river • Forest River • Gladden • Greylin • Limlight • Nimrodel • Redwater • River Running|
|Anduin • Ciril • Erui • Gilrain • Harnen • Lefnui • Mering Stream • Poros • Ringló • Serni|
|Adorn • Entwash • Isen • Mering Stream • Snowbourn|
|Brandywine River • The Water • Shirebourn|
|Adurant • Ascar • Brilthor • Duilwen • Gelion • Legolin • Little Gelion • Thalos|
|Aros • Dry River • Esgalduin • Mindeb • Narog • Rivil • Taeglin|
|Brithon • Celebros • Celon • Malduin • Ringwil • Sirion|
Translations around the worldEdit
|Foreign Language||Translated name|
|Chinese (Hong Kong)||艾辛|
- ↑ Unfinished Tales, Part Two: The Second Age, II: "Aldarion and Erendis: The Mariner's Wife", Notes
- ↑ The Atlas of Middle-earth, Regional Maps, "The White Mountains"
- ↑ 3.0 3.1 3.2 The Complete Guide to Middle-earth
- ↑ Unfinished Tales, Part Two: The Second Age, IV: "The History of Galadriel and Celeborn, and of Amroth King of Lórien"