Omonogawa, Akita

 was a town located in Hiraka District, Akita Prefecture, Japan.
In 2003, the town had an estimated population of 10,829 and a density of 147.13 persons per km². The total area was 73.60 km².
On October 1, 2005, Omonogawa, along with the towns of Hiraka, Jūmonji, Masuda and Ōmori; and the villages of Sannai and Taiyū (all from Hiraka District), was merged into the expanded city of Yokote.