This article is about the place in Mordor. For the fortress with a related name, see . Utumno
Orc armies that marched through Udûn to the Black Gates.
Udûn was a depressed valley located in northwestern Mordor. It laid between Cirith Gorgor and the Isenmouthe, and was traversed by large armies of Sauron in times of war.
Within its circumference were many Orc-holds (as told in
), including The Return of the King Durthang, the forges, and the forts at Carach Angren. 
Udûn originated with the creation of the lands of Mordor. During both the war of the
Last Alliance and the War of the Ring, the vast armies of Mordor passed through here and out the Black Gate to confront their enemies. 
meant "hell" in Udûn Sindarin.
Translations around the World Edit
Regional Maps, "Mordor (and Adjacent Lands)" The Atlas of Middle-earth, ↑ 2.0 2.1 2.2
The Complete Guide to Middle-earth