Mt. Charteris formerly severed as the secret headquarters for Factor Three, Professor Power, Secret Empire and the Sons of the Serpent. Crimson Cowl's Masters of Evil were using it as a base before the Thunderbolts eventually adopted it as their own hideout. The team eventually abandoned the mountain for Stormfront-1 but operations eventually returned to Thunderbolts Mountain when the Thunderbolts became an officially sanctioned Initiative team helmed by Norman Osborn.
After the Secret Invasion, Norman Osborn moved his operations to Avengers Tower and The Cube became the Thunderbolts base. After Osborn's Dark Reign was ended, Thunderbolts Mountain was used by him as a headquarters for the combined forces of A.I.M., H.A.M.M.E.R., The Hand and HYDRA as well as his second Dark Avengers.
It was last seen as a base of operations for a revitalized HYDRA under the rule of Madame Hydra following Osborn's defeat.