As of March 2007, the city has an estimated population of 698,946 and the density of 884.87 persons per km². The total area is 789.88 km². On January 22, 2007, the towns of Seto and Takebe merged into Okayama. The city was founded on June 1, 1889.
Sogenji is a very large zen monastery belonging to the Rinzai sect in the centre of the city. It has produced several of the abbots of the major monasteries in Kyoto. Under the direction of Shodo Harada Roshi it is now a training centre for foreign practitioners and allows women and lay people and as well as those participating on a part-time basis to as well as ordained men to participate.
Okayama University is located in the city, which founded as a medical school in 1870 and estabilished in 1949 as a university.
The city is one of few Japanese cities to have kept an operational tram system. It is a major rail interchange as trains from Shikoku connect with the Sanyō main line here.Okayama Airport serves the city.
The city became a core city in 1996. Later in March 22, 2005, the towns of Mitsu in Mitsu District and the town of Nadasaki from Kojima District were merged into the city, and on January 22, 2007, the town of Takebe from Mitsu District and Seto from Akaiwa District were also merged into the city. All three districts have since been dissolved.
After the merger and part of the negotiation with the Okayama Prefecture, the city slated to becoming a designated city in 2009.