The Ōito Line is a railway line in Japan which connects Matsumoto Station in Nagano Prefecture with Itoigawa Station in Niigata Prefecture. There are two operators on the line: East Japan Railway Company and West Japan Railway Company. Minami-Otari is the boundary for the two companies. The section of the line operated by JR East, between Minami-Otari and Matsumoto, is electrified and trains are fairly regular along this section. The JR West section from Minami-Otari to Itoigawa, however, is not electrified and sees less use. Trains operate less frequently along this section.

Niigata Prefecture is a prefecture in the Chūbu region of Honshu of Japan. Niigata Prefecture has a population of 2,131,009 and is the fifth-largest prefecture of Japan by geographic area at 12,584.18 km2 (4,858.78 sq mi). Niigata Prefecture borders Toyama Prefecture and Nagano Prefecture to the southwest, Gunma Prefecture to the south, Fukushima Prefecture to the east, and Yamagata Prefecture to the northeast.