alagogshak is a stratovolcano, located on the alaska peninsula, united states, in katmai national park and preserve. it is the oldest of the volcanoes in the vicinity of the valley of ten thousand smokes. the volcano was recognized as a separate feature from mount martin in 1997. the holocene mount martin stands partly on alagogshak's deeply eroded edifice, about northeast of the alagogshak vent. alagogshak was last active in pleistocene time, and was active from about 680,000 years before present to about 43,000 years before present. the remnant summit crater consists of hydrothermally altered rock. it is the only member of the katmai volcanic group that is no longer active.