Which country contains the world's largest active volcano by volume, Mauna Loa?

The United States contains Mauna Loa, the world's largest active volcano by volume, on Hawaii's Big Island.

Mauna Loa rises about 4,169 metres above sea level, but its base extends deep beneath the Pacific seafloor. Measured from that underwater base, the volcano reaches far higher than its visible summit.

Its name means Long Mountain in Hawaiian, reflecting its broad, gently sloping shield-volcano form. Mauna Loa has erupted repeatedly since written records began in 1843, with its most recent eruption occurring in 2022.

Mauna Kea is taller when measured from the seafloor, but it is not currently considered active in the same way. Mount Everest is higher above sea level but is not a volcano.