The Suigun Line is a Japanese railway line operated by East Japan Railway Company, which connects Mito Station in Ibaraki Prefecture and Asaka-Nagamori Station in Fukushima Prefecture, Japan. All trains on the line continue onto the Tōhoku Main Line to Kōriyama Station. The name of the line includes one kanji from each of the terminals, Mito (水戸) and Kōriyama (郡山).

The Tōhoku Main Line is a 575.7-kilometre-long (357.7 mi) railway line in Japan operated by the East Japan Railway Company. The line starts from Tokyo Station in Chiyoda, Tokyo and passes through such cities as Saitama, Utsunomiya, Fukushima, and Sendai, before reaching the end of the line in Morioka. The line originally extended to Aomori, but was truncated upon the extension of the Tōhoku Shinkansen beyond Morioka, which mostly parallels the Tōhoku Main Line. A portion of the Tōhoku Main Line is also shared with the Keihin–Tōhoku Line and the Saikyō Line.