Hienuki (稗貫郡, Hienuki-gun) was a district located in Iwate Prefecture (formerly Rikuchu Province), Japan.
The district had an estimated population of 23,027 and the total area is 365.41 km2.
By the time of founding, the district was co-teminous with the city of Hanamaki.
Until the day before the dissolution (December 31, 2005), there were only two towns left in the district.
Therefore, Hienuki District was dissolved as a result of this merger.