Iioka (飯岡町, Iioka-machi) was a town located in Kaijō District, Chiba Prefecture, Japan. Iioka was a noted port town in the Edo period, and prospered greatly in the aftermath of the Great Fire of Meireki in 1657, as a transshipment center for timber and building materials to Edo. Modern Iioka was formed on April 1, 1889. On March 31, 1954 it expanded through annexation of the villages of Sangawa and a part of Toyooka.