The Nayoro Main Line (名寄本線) was a rail line which was operated by Japanese National Railways and later under JR Hokkaido, which extended from Nayoro to Engaru, where it connected with the Sekihoku Main Line.

[1][2] In 1962, three services would start using the line - the Monbetsu, which ran between Sapporo and Engaru; the Asahikawa, which was a round trip service that made stops at Engaru and Nayoro before returning to Asahikawa; and the Tento, which ran between Okoppe and Abashiri.

[6] When the National Railways Restructuring Act was passed in 1980, the line was designated as a specified local line, but its abolition was delayed along with that of the Tempoku, Chihoku, and Shibetsu [ja] lines due to insufficient alternative transportation at that time, especially in winter.

It was proposed that the sections of the line between Nayoro and Shimokawa and between Monbetsu and Engaru be transferred to third-sector operation, as these sections were used most frequently by passengers.

[3][7] 9600 challenges Tenpoku Pass — 1972 short film by Japanese National Railways Media related to Nayoro Main Line at Wikimedia Commons