Yachimata was part of a region of horse ranches under the direct control of the Tokugawa shogunate in the Edo period. After the Meiji Restoration, the hamlet of Yachimata was founded on November 2, 1872 within Inba District, Chiba Prefecture. Yachimata was officially designated a village on April 1, 1889, and was elevated to town status on January 1, 1919. The village expanded in 1954 through annexation of a portion of neighboring Hyuga Village in Sanbu District and by merging with the village of Kawakami on November 1, 1954. Yachimata was elevated to city status on April 1, 1992.