Okagaki is a town located in Onga District, Fukuoka Prefecture, Japan. As of 31 December 2023, the town had an estimated population of 31,553 in 14376 households, and a population density of 490 persons per km2. The total area of the town is 48.64 km2 (18.78 sq mi).

Fukuoka Prefecture is a prefecture of Japan located on the island of Kyūshū. Fukuoka Prefecture has a population of 5,109,323 and has a geographic area of 4,986 km2. Fukuoka Prefecture borders Saga Prefecture to the southwest, Kumamoto Prefecture to the south, and Ōita Prefecture to the southeast.