Tyrrhenian Sea, Italy
42.34 N, 10.32 E
summit elevation 645 m
Volcano type unknown
Montecristo Island is located halfway between Corsica and Italy.
Further reading
Innocenti, Fabrizio, et al. "The Montecristo monzogranite (Northern Tyrrhenian Sea, Italy): a collisional pluton in an extensional setting." Geological Journal 32.2 (1997): 131-151.
Unknown eruptions.