Kosi division(Hindi: कोसी प्रमंडल) is an administrative geographical unit of Bihar state of India. Saharsa is the administrative headquarters of the division. Currently (2005), the division consists of Saharsa district, Madhepura district, and Supaul district.
Coordinates: 25°53′N 86°36′E / 25.88°N 86.6°E