On February 13, 2005, Yamaguchi, along the towns of Fukuoka, Sakashita and Tsukechi, and the villages of Hirukawa, Kashimo and Kawaue (all from Ena District, Gifu Prefecture), was merged into the expanded city of Nakatsugawa in Gifu Prefecture and no longer exists as an independent municipality.
- "中津川市紹介（HP版）07.03.27" (PDF). Nakatsugawa official website (in Japanese). Retrieved August 19, 2011.
- Nakatsugawa official website (Japanese)