Note: the entire island is high-level, "average" here isn't the same as Skyrim! Threat levels assume you're ready to tackle Dragonborn content!
Benkongerike
Occupants
Bristlebacks / Rieklings
Special Features
Word Wall: Cyclone
Important Treasure
Black Book: Untold Legends East Empire Pendant
Ore Veins
x1 Stalhrim; x4 Silver
Tactical
Threat Level: Average
Bristleback Cave
Occupants
Bristlebacks / Rieklings
Special Features
None
Important Treasure
None
Tactical
Threat Level: Average
Broken Tusk Mine
Occupants
Rieklings
Special Features
None
Important Treasure
None
Ore Veins
x2 Heart Stone
Tactical
Threat Level: Average
Castle Karstaag Caverns
Occupants
Bristlebacks / Rieklings
Special Features
None
Important Treasure
None
Tactical
Threat Level: Average
Castle Karstaag Ruins
Occupants
Rieklings / Kartaag*
Special Features
None
Important Treasure
Summon Karstaag *
Tactical
Threat Level: Average - *Endgame, if summoning Karstaag.
Coldcinder Cave
Occupants
Ash Spawn / Netch / Skeever
Special Features
None
Important Treasure
None
Ore Veins
x3 Heart Stone
Tactical
Threat Level: Dangerous
Damphall Mine
Occupants
Reavers
Special Features
Alchemy Lab; Fishing Supplies; Forge/Anvil; Smelter; Tanning Rack; Wood Chopping
Important Treasure
None
Ore Veins
x2 Iron; x1 Silver
Tactical
Threat Level: Average
Frossel
Occupants
Bristlebacks / Rieklings
Special Features
None
Important Treasure
None
Ore Veins
x5 Gold
Tactical
Threat Level:
Frostmoon Crag
Occupants
Werewolves
Special Features
Tanning Rack
Important Treasure
None
Interesting Notes
You will be welcomed if you're a werewolf, and can purchase Blessed Rings of Hircine.
Tactical
Threat Level: Dangerous
Glacial Cave
Occupants
Horkers / Rieklings
Special Features
None
Important Treasure
East Empire Pendant Karstaag's Skull
Ore Veins
x1 Malachite
Tactical
Threat Level: Average
Hrothmund's Barrow
Occupants
None
Special Features
None
Important Treasure
None
Ore Veins
x1 Silver; x1 Gold
Tactical
Threat Level: None
Moespring Pass
Occupants
Rieklings
Special Features
None
Important Treasure
None
Tactical
Threat Level: Average
Raven Rock Mine
Occupants
Draugr / Frostbite Spiders / Skeevers
Special Features
Alchemy Lab; Arcane Enchanter; Grindstone; Smelter; Wood Chopping; Word Wall: Dragon Aspect
Important Treasure
Bloodskal Blade
Ore Veins
x9 Ebony; x2 Stalhrim
Tactical
Threat Level: Difficult
Fahlbtharz
Occupants
Albinoe Spiders / Automatons / Oil Spiders / Rieklings
Special Features
None
Important Treasure
Kagrumez Resonance Gem Visage of Mzund
Tactical
Threat Level: Dangerous
Kagrumez
Occupants
Automatons / Reavers / Enchanted Sphere
Special Features
None
Important Treasure
Dwarven Black Bow of Fate Steadfast Dwarven Spider Steadfast Dwarven Sphere
Interesting Notes
Yay! Automaton followers! Be aware you can only Automaton follower at any given time. If they die or you want to swap out, come back here to do that.
Tactical
Threat Level: Periloous
Nchardak
Occupants
Automatons / Reavers / Enchanted Sphere
Special Features
Tanning Rack
Important Treasure
Black Book: Epistolary Acumen
Ore Veins
x4 Malachite
Tactical
Threat Level: Perilous
Forts, Nordic Towers & Watchtowers
Ashfallow Citadel
Occupants
Morag Tong Assassins
Special Features
Alchemy Lab; Arcane Enchanter
Important Treasure
None
Tactical
Threat Level: Average
Fort Frostmoth
Occupants
Ash Spawn / General Falx Carius
Special Features
None
Important Treasure
Champion's Cudgel
Ore Veins
x3 Ruby Geodes; x2 Heart Stone
Tactical
Threat Level: Dangerous
Highpoint Tower
Occupants
Albine Spiders / Ash Spawn / Ash Guardian / Illdari Sarothril
Special Features
Alchemy Lab; Arcane Enchanter; Wood Chopping
Important Treasure
None
Ore Veins
x1 Amethyst; x1 Emerald; x2 Ruby; x4 Sapphire; x3 Orichalcum; x1 Gold
Tactical
Threat Level: Dangerous
Bloodskal Barrow
Occupants
Reavers / Dragon Priest Zahkriisos
Special Features
Alchemy Lab; Cooking Pot/Spit; Tanning Rack; Wood Chopping
Important Treasure
Black Book: The Winds of Change Dragon Priest Mask: Zahkriisos
Ore Veins
x1 Stalhrim; x1 Emerald (outside, SE of entrance); x1 Gold (outside, SE of entrance)
Tactical
Threat Level: Perilous - Zahkriisos specialises in lightning magic.
Gyldenhul Barrow
Occupants
Garuk Windrime / Haknir Death-Brand / Haknir's Crew / Thalin Ebonhand
Special Features
None
Important Treasure
Bloodscythe Soulrender
Tactical
Threat Level: Difficult - You'll need all 4 pieces of the Deathbrand armor to fully complete this dungeon.
Kolbjorn Barrow
Occupants
Dragon Priest Ahzidal / Albino Spiders / Draugr / Poison Spiders
Special Features
Word Wall: Cyclone
Important Treasure
Ahzidal's Armor Set Ahzidal's Ring of Arcana Ahzidal's Ring of Necromancy Dragon Priest Mask: Ahzidal
Tactical
Threat Level: Perilous - Ahzidal specializes in fire magic and can reanimate the dead.
Snowclad Ruins
Occupants
Werebears
Special Features
None
Important Treasure
None
Tactical
Threat Level: Dangerous
Vahlok's Tomb
Occupants
Corrupted Shades / Draugr / Vahlok the Jailor
Special Features
Word Wall: Battle Fury
Important Treasure
None
Tactical
Threat Level: Perilous - Valhok is a Dragon Priest that specializes in Fire magic, as well as being able to both Summon Flame Atronachs and Command Daedra.
White Ridge Barrow
Occupants
Albino Spiders / Bandits / Draugr / Dragon Priest Dukaan / Flame Spiders / Merilar Rendas
Special Features
Word Wall: Cyclone
Important Treasure
Black Book: The Sallow Regent Dragon Priest Mask: Dukaan
Interesting Notes
The Imbuing Chamber here allows for the creation of Spider Scrolls
Ore Veins
x13 Ruby; x2 Sapphire; x2 Heart Stone
Tactical
Threat Level: Perilous - Dukaan specializes in frost magic and can summon Seekers.