The name of Nishio appears in the record of Tokugawa Ieyasu after the battle of Okehazama.
Nishio is famous for its tea, called Nishio-cha. It is used for Maccha. The share is 20% and it is the highest share of Maccha in Japan.
Nishio Castle was built in 1221 by Ashikaga Yoshiuji.