Rikuu West Line

The line was built from the Shinjō end in stages during the 1910s. The first section, from Shinjō to Furukuchi (17.0 km), opened on 7 December 1913 as the Sakata Line (酒田線). It was extended from Furukuchi to Kiyokawa (14.1 km) on 14 June 1914, from Kiyokawa to Karikawa (3.8 km) on 16 August 1914, and finally from Karikawa to Amarume (8.1 km) on 20 September 1914, completing the route down the Mogami valley.

The line's identity was reshaped in step with the railways around it. On 1 November 1917, following the completion of the Rikuu East Line, the Sakata Line — by then running Shinjō–Sakata together with a Sakata–Mogamigawa freight branch — was renamed the Rikuu West Line. On 20 April 1924, when the Ugo-Kameda–Ugo-Iwaya section opened and linked up with the Uetsu North Line, the network was reorganised: the Rikuu West Line was redefined as the Shinjō–Amarume section it occupies today, while the Akita–Nezugaseki stretch was folded into the Uetsu Line.

On 1 April 1958 all passenger trains were replaced with diesel railcars, ending steam haulage. With the privatisation of Japanese National Railways on 1 April 1987, the East Japan Railway Company inherited the line and freight operations over its whole length were discontinued. Centralised traffic control (CTC) was commissioned on 28 February 1991.

On 4 December 1999 the publicly chosen nickname "Oku-no-Hosomichi Mogamigawa Line" came into use. KiHa 110 series diesel railcars work the local services, which run the length of the line; some continue beyond Amarume onto the Uetsu Main Line toward Sakata, the historic destination from which the route first took its name.

From 14 May 2022 the entire line suspended train operations and switched to substitute bus service, to allow construction work connected with the (provisional) Takaya Tunnel — part of the Takaya Road, a component of the "Shinjō–Sakata Road" regional high-standard highway. The suspension was originally planned to last until fiscal 2024, but delays to the tunnel work pushed back its end.

On 26 September 2025 the date for resuming rail service and ending the substitute buses was announced. Rail service resumed across the whole line on 16 January 2026, but trains no longer stop at the very lightly used Uzen-Zennami and Takaya stations.

10 stations tracked on the map, listed alphabetically. Select any to read its page.

• Amarume余目
• Furukuchi古口
• Karikawa狩川
• Kiyokawa清川
• Masukata升形
• Minamino南野
• Shinjo新庄
• Takaya高屋
• Tsuya津谷
• Uzen-Zennami羽前前波

• 19137 December: the Shinjō–Furukuchi section (17.0 km) opens as the Sakata Line.
• 191414 June: the line is extended from Furukuchi to Kiyokawa (14.1 km).
• 191416 August: the Kiyokawa–Karikawa section (3.8 km) opens.
• 191420 September: the Karikawa–Amarume section (8.1 km) opens, completing the line down the Mogami valley to Amarume.
• 19171 November: following the completion of the Rikuu East Line, the Sakata Line (then Shinjō–Sakata plus the Sakata–Mogamigawa freight branch) is renamed the Rikuu West Line.
• 192420 April: the Ugo-Kameda–Ugo-Iwaya section opens and connects with the Uetsu North Line; the network is reorganised, redefining the Rikuu West Line as the Shinjō–Amarume section and folding the Akita–Nezugaseki stretch into the Uetsu Line.
• 19581 April: all passenger trains are replaced with diesel railcars, ending steam haulage.
• 19871 April: with the privatisation of Japanese National Railways, JR East inherits the line and freight operations over the whole line are discontinued.
• 199128 February: centralised traffic control (CTC) is commissioned over the line.
• 19994 December: the publicly chosen nickname 'Oku-no-Hosomichi Mogamigawa Line' comes into use.
• 202214 May: the whole line suspends train operations and switches to substitute buses for construction work connected with the (provisional) Takaya Tunnel on the Takaya Road, part of the 'Shinjō–Sakata Road' regional high-standard highway.
• 202526 September: the date for resuming Rikuu West Line service and ending the substitute buses is announced.
• 202616 January: rail service resumes across the whole line, but trains no longer stop at the very lightly used Uzen-Zennami and Takaya stations.