Koraku-en was built in 1867 over a period of 3 years and originally received the name of Koen, or later garden, as it was made following the construction of Okayama Castle. It served as a private garden and spa for the local feudal lord and to entertain important guests, although it was occasionally opened to the public. In 1884, after the abolition of the feudal system, the ownership of Koraku-en was transferred to the prefecture of Okayama and has been opened to the public since then.
Nowadays Koraku-en retains its original appearance from 1700, but several elements have been restored following pictures and diagrams from the Edo Period, since it suffered serious damage by flooding in 1934 and by air raids during World War 2. The garden was built in a style known as Kaiyu, featuring several ponds, lawns, hills and tree houses connected by walking paths which offer an scenic view at every turn.