Nagi is a town located in Katsuta District, Okayama Prefecture, Japan. As of 1 September 2022, the town had an estimated population of 5,738 in 1512 households and a population density of 83 persons per km². The total area of the town is 69.52 square kilometres (26.84 sq mi).

Okayama Prefecture is a prefecture of Japan located in the Chūgoku region of Honshu. Okayama Prefecture has a population of 1,906,464 and has a geographic area of 7,114 km2. Okayama Prefecture borders Tottori Prefecture to the north, Hyōgo Prefecture to the east, and Hiroshima Prefecture to the west.