Ichikawa, city, western Chiba ken (prefecture), east-central Honshu, Japan. It lies along the Edo River, across which it borders Tokyo to the west, and it is just northwest of Funabashi. It is an important component of the Tokyo-Yokohama metropolitan area.
The city is an amalgamation of the three towns of Ichikawa, Yawata, and Nakayama, which were salt-producing post towns on the Chiba Highway (Chiba-kaidō) during the Edo (Tokugawa) period (1603–1867). Since the opening of two railway lines in 1894, the city has served as a commercial, industrial, and residential suburb of Tokyo. Ichikawa houses educational institutions. The cultivation of vegetables and fruit on the plateaus to the north is important. Pop. (2005) 466,608; (2010) 473,919.