This is a tricky ranking because it depends on whether you count *active* volcanoes or *total* volcanoes. Indonesia has the most 'active' volcanoes in the world and has suffered the most casualties from eruptions due to its high population density. However, the United States actually has the highest number of *total* volcanoes (including dormant ones), with about 173. Most of these are located in Alaska and the Aleutian Islands. If you look for the country with the most volcanoes per square mile, the winner is usually Iceland. The 'Ring of Fire,' which encircles the Pacific Ocean, is home to 75% of the world's volcanoes and 90% of the world's earthquakes.