NishioCity's Saijo Castle dates from the year of Jokyu (1221), and is said to have been built by the great warrior Yoshiuji Ashikaga.
An official municipal organization was established in Nishio in 1953, and the city has become the focal point of the southern West Mikawa area.
Furthermore, the people of NishioCity, the castle town of 60,000 koku,' are determined to preserve their rich natural and cultural heritage to ensure that it is passed on for the enjoyment of future generations.