These are all of the ruined forts in Cyrodiil.
- Arkved's Tower — A large fort southwest of Cheydinhal containing daedra (quest-related). (map)
- Crowhaven — A medium-sized fort northwest of Anvil containing vampires (quest-related). (map)
- Dasek Moor — A medium-sized fort south of Kvatch containing marauders and undead. (map)
- Fathis Aren's Tower — A medium-sized fort south of Bravil containing conjurers, daedra, and dremora (quest-related). (map)
- Fort Alessia — A medium-sized fort between the Imperial City and Bravil containing marauders. (map)
- Fort Ash — A medium-sized fort between the Imperial City and Chorrol containing goblins. (map)
- Fort Aurus — A small fort northeast of Bravil, across the Niben Bay, containing conjurers (quest-related). (map)
- Fort Black Boot — A small fort between Bravil and Skingrad containing conjurers. (map)
- Fort Blueblood — A medium-sized fort southeast of Leyawiin containing marauders (quest-related). (map)
- Fort Bulwark — A medium-sized fort northeast of Leyawiin containing conjurers (plugin-specific). (map)
- Fort Caractacus — A small fort north of the Imperial City containing conjurers (quest-related). (map)
- Fort Carmala — A small fort between Chorrol and Skingrad containing vampires (quest-related). (map)
- Fort Cedrian — A medium-sized fort between Bravil and Cheydinhal containing marauders. (map)
- Fort Chalman — A small fort northeast of the Imperial City containing undead. (map)
- Fort Coldcorn — A small fort between the Imperial City and Chorrol containing monsters (quest-related). (map)
- Fort Cuptor — A medium-sized fort far east of Bravil containing necromancers. (map)
- Fort Dirich — A small fort between Skingrad and Chorrol containing undead (quest-related). (map)
- Fort Doublecross — A medium-sized fort northeast of Leyawiin containing necromancers. (map)
- Fort Empire — A medium-sized fort northwest of the Imperial City containing monsters. (map)
- Fort Entius — A medium-sized fort far east of Bravil containing conjurers. (map)
- Fort Facian — A medium-sized fort southeast of Cheydinhal containing undead. (map)
- Fort Farragut — A small fort east of Cheydinhal containing undead (quest-related). (map)
- Fort Flecia — A small fort east of Bravil containing goblins. (map)
- Fort Gold-Throat — A small fort east of Bravil containing goblins. (map)
- Fort Grief — A medium-sized fort northeast of Bravil containing NPCs (quest-locked). (map)
- Fort Hastrel — A medium-sized fort north of Kvatch containing vampires. (map)
- Fort Homestead — A medium-sized fort south of the Imperial City containing marauders. (map)
- Fort Horunn — A medium-sized fort between Bruma and Cheydinhal containing monsters. (map)
- Fort Irony — A small fort southeast of Bravil containing goblins (quest-related). (map)
- Fort Istirus — A medium-sized fort between Skingrad and Kvatch containing necromancers. (map)
- Fort Linchal — A medium-sized fort north of Kvatch containing necromancers. (map)
- Fort Magia — A medium-sized fort east of the Imperial City containing undead (quest-related). (map)
- Fort Naso — A small fort south of Cheydinhal containing vampires. (map)
- Fort Nikel — A small fort west of the Imperial City containing bandits and marauders. (map)
- Fort Nomore — A medium-sized fort between Bravil and Leyawiin containing monsters. (map)
- Fort Ontus — A medium-sized fort between Chorrol and Kvatch containing necromancers (quest-related). (map)
- Fort Pale Pass — A large fort hidden deep in the mountains northeast of Bruma containing undead Akaviri soldiers (quest-related).
- Fort Rayles — A medium-sized fort northwest of Chorrol containing conjurers. (map)
- Fort Redman — A medium-sized fort between Bravil and Leyawiin containing vampires. (map)
- Fort Redwater — A medium-sized fort far east of Bravil containing vampires. (map)
- Fort Roebeck — A medium-sized fort south of the Imperial City containing conjurers. (map)
- Fort Scinia — A medium-sized fort east of Cheydinhal containing marauders and undead (quest-related). (map)
- Fort Sejanus — A medium-sized fort southeast of the Imperial City containing conjurers. (map)
- Fort Strand — A medium-sized fort east of Anvil containing marauders (quest-related). (map)
- Fort Sutch — A small fort north of Anvil containing mercenaries (quest-related). (map)
- Fort Teleman — A medium-sized fort northeast of Leyawiin containing necromancers. (map)
- Fort Urasek — A medium-sized fort east of the Imperial City containing goblins. (map)
- Fort Variela — A medium-sized fort between Bravil and the Imperial City containing necromancers. (map)
- Fort Virtue — A small fort southwest of the Imperial City containing undead. (map)
- Fort Vlastarus — A small fort east of Skingrad containing vampires (quest-related). (map)
- Fort Wariel — A small fort northwest of Kvatch containing marauders. (map)
- Fort Wooden Hand — A medium-sized fort between Chorrol and Skingrad containing marauders. (map)
- Frostcrag Spire — A tower east of Bruma that serves as a home for magic-oriented characters (plugin-specific). (map)
- Sancre Tor — A large fort north of Chorrol containing undead (quest-related). (map)
- Sundercliff Watch — A fort far east of Bravil containing NPCs and vampires (add-on-specific). The location is added with the Unearthing Mehrunes Razor official add-on, and houses the eponymous artifact.
Sundercliff Watch is the largest dungeon in the game, containing a mixture of caves, buildings and Ayleid ruins. The location consists of 23 zones in total. The nine main zones are Sundercliff Watch, Sundercliff Village, Sundercliff Commune, Sundercliff Forge, Sundercliff Mines, Excavated Ruin, Varsa Baalim, Nefarivigum, and Forgotten Tunnels. Three smaller zones, Cava Arpenia, Cava Beldameld and Cava Marspanga link different areas of Varsa Baalim together, and in addition, there are multiple houses, side rooms and tents. (map)
Notes
The sizes (small, medium or large) of Ayleid Ruins, Forts, Mines and Caves are related to the number of zones they contain as follows:
- Small: One zone
- Medium: Two or three zones
- Large: Four or more zones