The Keystone Mountain House is nestled at the bottom of Dercum Mountain. This was Keystone's original base area. With its convenient location and excellent skier services including: children's ski school, children's center, retail shops & lift ticket office, The Mountain House in Keystone is the perfect place for your Keystone lodging needs. Simply step on the Argentine Lift and Peru Express and you'll be carried to the top of some of Keystone's favorite terrain.