Ina Basin

A long narrow basin along the Tenryu River in the southern part of Nagano Prefecture. It is often colloquially called the Ina Valley. It is bounded by the Kiso Mountains to the west and the Ina Mountains to the east, and the width from east to west between these two is only about 5 kilometers. The altitude is 700 meters in the north and 400 meters in the south. The basin stretches from Tatsuno Town at the northern end to Tenryukyo in Iida City in the south, and is bounded to the south by the Akaishi Mountains to the southwest, so the basin's entrance is only in the north. It is about 60 kilometers long from north to south. The flat land consists of 6 to 7 river terraces formed by the Tenryu River, and to the west it consists of alluvial fans formed by large and small tributaries of the Tenryu River that flow over them. Until the early 1960s, there were few factories, and it was a farming village where 20th century pears and apples, dairy farming, sericulture, etc. were cultivated, and it had the character of a dead-end road entered from the northern end. Since the 1970s, the Chuo Expressway has run north to south, and as a result of closer connections with Nagoya, factories, large stores, hotels, etc. have been opening up. The central city in the northern half is Ina City, and in the southern half is Iida City.

[Hiroyoshi Kobayashi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

長野県南部、天竜川に沿う狭長な盆地。慣用的に伊那谷とよばれることも多い。西は木曽山脈(きそさんみゃく)で、東は伊那山地で限られ、この間の東西の幅は5キロメートル内外しかない。標高は北部で700メートル、南部で400メートル。盆地は北端の辰野(たつの)町から南は飯田(いいだ)市の天竜峡までで、この南方は南西方向へ向かう赤石山脈で限られるので、盆地の入口は地形的には北方だけしかない。南北の長さは60キロメートルほどある。平地は天竜川の形成した6～7段の河岸段丘と、西側はこの上に流出した天竜川の大小の支流の形成する扇状地からなる。昭和40年代初期までは工場の進出も少なく、二十世紀ナシとリンゴ、酪農、養蚕などの行われる農村であり、北端から入る袋小路的な性格をもっていた。昭和50年代からは、中央自動車道が南北に縦貫し、名古屋方面との連絡が密接になった結果、工場や大型商店、ホテルなども進出している。北半部の中心都市は伊那市で南半部は飯田市である。

［小林寛義］

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