Ichinoseki (一関市, Ichinoseki-shi) is a city located in Iwate Prefecture, in the Tōhoku region of northern Japan.

Ichinoseki is located inland in the south of Iwate Prefecture, a little over two hours north of Tokyo by the Tōhoku Shinkansen.

A large volume of extremely stable granite rock runs beneath the city, and is the center of a site being promoted as a suitable location for construction of the International Linear Collider (ILC).

[3] The agricultural makeup of the city outside the centre is mostly composed of farmers, leading to an influx of Chinese and Filipino immigrants due to marriage.

It was raised to city status on April 1, 1948 by the merger of the towns of Ichinoseki and Yamame with the villages of Mataki and Nakasato.