Northern Marianas Islands is in the Pacific Ocean, east of the Philippines and south of Japan. The approximately 16 coral and volcanic islands, including all of the Mariana Islands except Guam, comprise an area of 464 sq km (179 sq mi). The principal islands are Saipan (122 sq km/47 sq mi), Tinian (101 sq km/39 sq mi), and Rota (83 sq km/32 sq mi). The island of Saipan contains the seat of government, a busy seaport, and an international airport.