Igarashi River

A tributary of the Shinano River that crosses the center of Niigata Prefecture. It originates from Mt. Eboshi (1,350 meters) near the border between Niigata and Fukushima Prefectures, flows through the Shimoda Basin, and joins the Shinano River in Sanjo City. It is 40.8 kilometers long. The upper Shimoda Basin was the property of the Igarashi clan in the Middle Ages, and is home to the Igarashi Shrine, a shrine listed in the Shikinaisho (Engineering Law), and the scenic spot of Yagigahana. The Igarashi River splits into the Oya River and the Sumon River at Yagigahana, and the Kasabori Dam is located on the Oya River. It is also known as a dense habitat for Japanese serows (a nationally designated natural monument). The Sumon River valley is the mountain path of the old Yashirogoe, and construction is underway to complete the construction of National Route 289. In the early modern period, Shimoda-go was a production area for charcoal for the Sanjo metalworking industry, and it was transported to Sanjo by water along the Igarashi River. Recently, efforts have been focused on tourism development, taking advantage of the development of dams in the hinterland.

[Hisao Yamazaki]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

新潟県の中央を横断する信濃川(しなのがわ)の支流。源を新潟・福島県境付近にある烏帽子(えぼし)山（1350メートル）に発し、下田盆地(しただぼんち)を流れて三条市で信濃川に合流する。延長40.8キロメートル。上流の下田盆地は中世、五十嵐氏の所領で、式内社五十嵐神社や八木ヶ鼻(やぎがはな)の名勝地がある。五十嵐川は八木ヶ鼻で大谷(おおや)川と守門(すもん)川に分かれ、大谷川筋には笠堀(かさぼり)ダムがあり、また、ニホンカモシカの密集生息地（国指定天然記念物）として知られる。守門川の谷は旧八十里越(ごえ)の山路で、国道289号の全通に向け工事が進められている。近世、下田郷(ごう)は三条金物の鍛冶炭(かじたん)産地で、五十嵐川の水運を利用して三条に運ばれた。最近は奥地のダム開発を生かした観光開発に力が注がれている。

［山崎久雄］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例