The range is the longest range in Japan and stretches 500 km (311 mi) south from the Natsudomari Peninsula of Aomori Prefecture to the Nasu volcanoes at the northern boundary of the Kantō region.

The highest point in the range is Mount Iwate, 2,038 metres (6,686 ft).

These mountains previously formed the boundary between historical provinces of Mutsu (陸奥国) and Dewa (出羽国).

The Ōu Mountains began to form in the Pliocene.

A chain of Quaternary volcanoes along the range forms the volcanic front.