Omonogawa (雄物川町; -machi) was a town located in Hiraka District, Akita, Japan.
On October 1, 2005, the towns of Hiraka, Jūmonji, Masuda, Omonogawa, Ōmori, and the villages of Sannai, and Taiyū, all from Hiraka District, merged into the city of Yokote.
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.