The damn thing covers something like half of the island. They said lava got within 5 miles of Hilo in an earlier eruption. Hilo is damn far from the cone, but when there is gravity helping you at 13,500 feet...lava can flow quite far.
Mauna Kea is taller, but Loa is greater with respect to volume.
Biggest on Earth.
And fast! Wouldn’t want to live anywhere near an active volcano.