October 1, 1921 - Tomitaka village becomes the town of Tomitaka by through the town system. (3 towns and 15 villages)
April 1, 1923 - The county council is abolished. The county office remains.
July 1, 1926 - The county government office is abolished. After that, it will be called Area Classification.
April 1, 1930 - Nobeoka Town, Okatomi Village, Tsunetomi Village merged, Nobeoka Town was reestablished. (3 towns and 13 villages)
February 11, 1933 - Nobeoka Town became the city of Nobeoka by through the city system and left the county. (2 towns and 13 villages)
October 25, 1936 - Igata Village and Tokai-mura are incorporated into the city of Nobeoka. (3 towns and 10 villages)
October 1, 1937 - Tomishima Town was reestablished through the merger of Tomitaka Town and Hososhima Town . (2 towns and 10 villages)
April 1, 1949 -
Nishiusuki district Morotsuka-shiiba changes counties. (2 towns and 12 villages)
April 1, 1951 - Toshima and Iwawaki-mura merged to form the city of Hyuga , leaving the county. (1 town and 11 villages)
April 1, 1955 - Minakata Village and Minamiura Village transferred to Nobeoka City. (1 town 9 villages)
April 1, 1969- Togo Town becomes the township of Togo Town. (2 towns and 8 villages)
January 11, 1972 - Kitagawa-mura becomes the town of Kitagawa through enforcement of the town system. Kitaura Village also becomes the town of Kitaura.
January 1, 2006 - Misato Town is established by the merger of Nango Village, Saigo Village, and Kitago Village. (6 towns and 2 villages)
February 20, 2006 - Kitakata and Kitaura are transferred to Nobeoka. (4 towns and 2 villages)[1]
February 25, 2006 - Togo Town is incorporated into Hyuga City. (3 towns and 2 villages)
March 31, 2007 - The town of Kitagawa is incorporated into Nobeoka. (2 towns and 2 villages)