They are the southern part of a submerged mountain range that extends 1,565 miles from Guam to near Japan. The Marianas are the northern most islands of a larger island group called Micronesia. The Marianas have a total land area of 396 square miles. Guam is a United States territory, and the rest of the Mariana Islands are a United States of America commonwealth called Northern Mariana Islands.
Following the Spanish-American War, Spain ceeded the southern part of the group to the United States, and sold the northern remainder to Germany. After World War I the former German islands were entrusted by the League of Nations to the control of Japan.