Waga in the Ōu Mountains it flows from north to south through the entire length of Nishiwaga Town before turning east through Kitakami City.

In prehistoric times the Waga River valley was occupied by the Jōmon people whose artifacts can be found in many places.

Stone "swords", tablets and tools as well as clay figurines, earrings, potsherds and even a shark's tooth were found from the Final Jōmon Period (1,300 - 300 BC).

[1] In 1945 a small prisoner of war camp was established on the south side of the river in the area now known as Lake Kinshu.

In the same year a small aircraft factory was built in some caves on the north side of the river near the Ishibane Dam.