Mount Fuji was a volcano in Japan, the largest mountain in the former country.
Background
The archaeologist exam at the Pioneer Scout camp has a question that directly references the mountain. It asks "Alfonso took a trip to Europe and saw the ruins of Pompeii. He learned that a famous volcano erupted, and buried the city in ash. Which volcano?" Mount Fuji is provided as an incorrect answer to the question.[1]
Appearances
Mount Fuji is mentioned only in the Fallout 76 update Wild Appalachia.