Carn Dum  

Zone: Angmar
Type: Ruins
Level: 47 - 50
Quests: Starting: 18, Involved: 13
Mobs: 45
Carm Dum
"Carm Dum, the capital of Angmar and the former stronghold of Witch-king. Angmar's shadow has returned to this city in the form of the False King, Mordirith, Steward of Angmar."

LOTRO Wiki Description

"Peer into the frightening fortress-city of Carn Dûm, built upon the slopes of the Mountains of Angmar by the Witch-king, who ruled with an iron fist. Though the Witch-king was driven out ages ago by an army of Elves and Men, rumours abound with stories that Carn Dûm stands poised to strike…"

It lies in northern Angmar, with the entrance located at approximately (11.1N, 33.6W).