The
Mariana Islands (also
the Marianas) are a crescent-shaped
archipelago comprising the summits of fifteen mostly dormant volcanic mountains in the western
North Pacific Ocean, between the
12th and
21st parallels north and along the
145th meridian east. They lie south-southeast of Japan, west-southwest of Hawaii, north of New Guinea and east of the Philippines, demarcating the
Philippine Sea's eastern limit. They are found in the northern part of the western
Oceanic sub-region of
Micronesia, and are politically divided into two U.S. jurisdictions: the Commonwealth of the
Northern Mariana Islands and, at the southern end of the chain, the territory of
Guam.