The ancient county of in
Mutsu Province was divided into the counties of Ninohe, Sannohe, Kunohe and Kita in 1634. Under the
Tokugawa shogunate, Kunohe county consisted of 47 villages under the control of
Hachinohe Domain, 10 villages under the control of
Morioka Domain and one village under joint control. Following the
Meiji restoration Kunohe came under the new province of
Rikuchu Province, which became part of Iwate Prefecture in 1872. With the establishment of the district system in 1878, the area was divided into Kita-Kunohe District (32 villages) and Minami-Kunohe District (27 villages). With the establishment of the municipality system on April 1, 1889, the two districts were merged and reorganized into one town (Kuji) and 19 villages. Karumai was raised to town status on January 1, 1925, followed by Kuzumaki on December 25, 1940. However, Kuzumaki was transferred to
Iwate District in 1948. The town of Taneichi was created on April 1, 1951, followed by Osanai on June 1, 1952. Kuji was elevated to city status on November 3, 1954. • January 1, 2006 - The town of
Taneichi and the village of
Ōno (spelled "Ohno" by the town.) merged to form the new town of
Hirono. • March 6, 2006 - The village of
Yamagata merged with the city of
Kuji.