Koishikawa Kōrakuen Garden (小石川後楽園 ) is in Koishikawa, Bunkyō, Tokyo, adjacent to Tokyo Dome City.

The construction was started in 1629 by Yorifusa Mito, the Daimyo of Mito Tokugawa family, and was completed by his successor, Mitsukuni Mito, a very famous Daimyo in the early Edo period.

Mitsukuni adopted an opinion of a Chinese scholar and named this garden "Koraku-en" (Koraku means "enjoying afterwards") after a Chinese teaching of "a governor should worry before people and enjoy after people".

This garden is full of Chinese flavor under the influence of Mitsukuni.

Korakuen was appointed as the special place of scenic beauty and the special historic site based on the cultural properties protection law of Japan.

All through Japan, there are only seven premises which enjoy double appointments by this Law. They are Kinkakuji, Ginkakuji, Sampo-in of Dogoji all in Kyoto, the trace of Nibo-no-miya in the third line of Heijō-kyō left city in Nara, Itsukushima Shrine in Hiroshima and Hamarikyū and Kōrakuen in Tokyo.