It consists of a long string of the northernmost islands of the Northern Marianas, including (from north to south) Farallon de Pajaros, the Maug Islands, Asuncion, Agrihan, Pagan, Alamagan, Guguan, Zealandia Bank, Sarigan, Anatahan, and Farallon de Medinilla.
The total land area of the islands, including offshore islets and rocks, is 154.755 km2 (59.75 sq mi).
Many Northern Island inhabitants have secondary residences on Saipan due to economic, educational or other needs.
The mayor's office and municipality administration, traditionally in the village of Shomushon on Pagan, is now "in exile" on Saipan.
Agriculture and fishing are essentially the only economic activities, although on Pagan pozzolan mining became a small industry after the early-1980s volcanic eruptions.