Ōmama (大間々町, Ōmama-machi) was a town located in Yamada District, Gunma Prefecture, Japan.
On March 27, 2006, Ōmama, along with the town of Kasakake (from Nitta District), and the village of Azuma (from Seta District), was merged to create the city of Midori.[1]
みどり市は、平成18年3月27日に新田郡笠懸町、山田郡大間々町、勢多郡東村の2町1村が合併して誕生し、平成28年3月27日に誕生から10年を迎えました。