|“||One of the more well-known peaks in the snowy Grizzlies of Ambarino, Mount Hagen towers above Lake Isabella to the west and Beartooth Beck to the east, which provides the main pass through the western mountain range and joins up with the Dakota River further south.||„|
The mountain is located southeast of Lake Isabella. It is also the highest point of the explorable world.
Like most of Grizzles West, Mount Hagen in completely snowcapped and conditions are very harsh and brutal. Most of the terrain is rough and ridge like with trails running up the western side into Ewing Basin and the valley towards the lake. The south side is very steep with only a single valley with two trails being accessible. The north and east sides are either to steep to climb or require alternate routes upward.
It later appears as the main setting of the mission "American Venom", where John Marston, Sadie Adler, and Charles Smith fight Micah's gang in order to get revenge for Arthur's death. Sadie and Charles are wounded, but John fights his way to the top, confronting Micah. Dutch exits the cabin and eventually betrays Micah, mortally wounding him with a shot to the chest and subsequently allowing John to finish Micah off once and for all.
During the credits, Bureau agents Edgar Ross and Archer Fordham visit the mountaintop, where they find Micah's corpse. They then begin a hunt for the killer, and eventually find the culprit, John Marston, at Beecher's Hope.
- At the top of the mountain can be found Rock Carving coordinates, as well as a frozen conquistador that wears the Morion Helmet.
- Southeast is a mountain hut. Upstairs is a lockbox that contains a coin sack and Aged Pirate Rum. Between the bunk beds and the ladder is Valerian Root tonic, sitting on top of a stump.
- Mount Hagen is named in honor of Landon Ricketts' voice actor, Ross Hagen, who passed away on May 7th, 2011.
- If visited after the mission "American Venom", Micah's frozen corpse can be found and his gun can be taken. However, his corpse disappears off-camera once his gun is taken.
- If visited by Arthur, some settlements such as tents seen in "American Venom" are absent, but wooden shacks such as the one where John confronts Dutch and Micah will be there.
- Once the mission "American Venom" is completed, players can no longer enter into the cabin.