The Mortrag Glacier was a large glacier once located along the northwestern coast of the island of Solstheim in the Moesring Mountains. Castle Karstaag was located just east of it. The interior of the glacier was used to host the Hunter's Game during the Bloodmoon Prophecy of 3E 427. The icy tunnels were filled with werewolves, the Hounds of Hircine. The Prince kidnapped four champions from the island and brought them to the glacier, to act as the Prey. The glacier was destroyed when an Aspect of Hircine was defeated by the Nerevarine, ending the Hunt and marking the first time that the Prey succeeded in killing the Hunter. The glacier subsequently collapsed, becoming a jagged ice field.
- Though the glacier is gone, Mortrag Peak of the Dragonborn expansion for TES V: Skyrim is one of the highest points in Solstheim.
- For more information, see the Bloodmoon article.