Okayama is the capital city of Okayama Prefecture in the Chūgoku region of Japan. The Okayama metropolitan area, centered around the city, has the largest urban employment zone in the Chugoku region of western Japan. The city was founded on June 1, 1889. As of February 2023, the city has an estimated population of 700,940 and a population density of 890 persons per km2. The total area is 789.95 square kilometres.

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.