The town of Ōhasama created on April 1, 1889 with the establishment of the municipalities system.
On January 1, 2006, Ōhasama, along with the town of Ishidoriya (from Hienuki District), and the town of Tōwa (from Waga District), was merged into the expanded city of Hanamaki (which lies to the south), and no longer exists as an independent municipality.