Mount Saint Helens is a volcano located in Skamania County, Washington in the Northwest region of the United States of America.


As the Olympians moved westward to the United States, Mount Saint Helens replaced Mount Etna as the prison of Typhon.

Percy Jackson and the Olympians

The Battle of the Labyrinth

When Percy Jackson and Annabeth Chase investigated Mount Saint Helens for Hephaestus, they locate a group of Telekhines forging the blade of Kronos' scythe. Percy called upon his power and caused the mountain to erupt. This weakened the seal on Typhon's prison and lead to a reaction within the mountain that awakened him. It was reported that numerous illnesses and minor injuries were caused by the eruption. In addition, half a million people in the area were evacuated.

The Last Olympian

The mountain kept erupting and was soon obliterated, torn apart and completely destroyed when Typhon escaped from under the mountain.



  • In real life, Mount Saint Helens was almost completely destroyed during an eruption in 1980.
  • During the 1980 eruption, the mountain lost 1,300 feet off of its peak.
Locations (CHB)
Magical Locations: Aeolia | Camp Half-Blood | Camp Jupiter | Cave of Trophonius | C.C.'s Spa and Resort | Daedalus' Workshop | Lotus Hotel and Casino | Mount Othrys | Ogygia | Olympus | Pan's Cave | Sea of Monsters | The Labyrinth | Tartarus | Underworld | Waystation
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Other Locations: Apennine Mountains | Aunty Em's Gnome Emporium | Carlsbad Caverns | Crusty's Water Bed Palace | Empire State Building | Gateway Arch | Grand Canyon | Greece | Hoover Dam | Junkyard of the Gods | Mississippi River | Mount Diablo | Mount Etna | Mount Saint Helens | Mount Tamalpais | Pikes Peak | Polyphemus' Island | Puerto Rico | ROFL | Rome | Triple G Ranch | United States Virgin Islands | Waterland