Betio is the largest township of Kiribati's capital city, South Tarawa, and the country's main port. The settlement is located on a separate islet at the extreme southwest of the atoll.

The Principality of Bethio (also spelled Bequio, Bekio, Bitio, Bétio or Beetyo) was a small monarchy located for centuries along the lower Senegal River valley, on the border between modern Mauritania and Senegal, in the northeast of Biffeche. In the 18th century it was also called the "Royaume d'Oral". Its capital was at Poum, then moved to N'Dombo, and finally moved to Ross, Senegal in the 19th century (called Ross-Bethio since then). The original, fertile farmlands of Bethio are in a region just east of the Djoudj National Bird Sanctuary.