Iwamotochō (岩本町?) is a district of Chiyoda, Tokyo, Japan. It consists of 3 chōme. This article also deals with Kanda-Iwamotochō (神田岩本町?). As of April 1, 2007, the total population of the two districts is 1,989.
Iwamotochō is located on the northeastern part of Chiyoda. The area consisting of both Iwamotochō and Kanda-Iwamotochō borders Kanda-Sakumakaji and Kanda-Sakumachō to the north; Higashi-Kanda to the east; Nihonbashi-Kodenmachō and Nihonbashi-Honchō, Chūō to the south; and Kanda-Sudachō, Kanda-Higashimatsushitachō, Kanda-Higashikonyachō, Kanda-Konyachō, Kanda-Nishifukudachō and Kanda-Mikurachō to the west.
Showa-Dori Avenue runs between Iwamotochō and Kanda-Iwamotochō. Iwamotochō, located east to the avenue, has already undergone modernization of the addressing system while, in Kanda-Iwamotochō, located west to the avenue, the modernization has not been enforced yet. In Chiyoda, many districts in the Kanda area has the prefix Kanda-; the addressing system modernization has not been enforced in such districts.