Nippon Tetsudō
The predecessor to the Aoimori Railway Line was completed as the – portion of the Nippon Railway on 1 September 1891. When the Nippon Railway was nationalized on 1 November 1906, it became part of the Japanese National Railways (JNR) system and was designated part of the Tōhoku Main Line on 12 October 1909. With the privatization and dissolution of JNR on 1 April 1987, the line came under the control of the East Japan Railway Company (JR East).