 Because of the inclusion of Alaska, the United States has the largest number of active volcanoes in the world, many of them geologically young.In Alaska, at least 50 volcanoes, including those in the Aleutian archipelago, have erupted in historical time.Alaska accounts for about 80% of the United States' volcanoes, excluding the seamounts in the area, about 8% of the world's volcanoes, and most of these are located among the Aleutian Islands.