Oka Domain was a feudal domain under the Tokugawa shogunate of Edo period Japan, in what is now central Ōita Prefecture. It was centered around Oka Castle in what is now the city of Taketa, Ōita and was ruled by the tozama daimyō Nakagawa clan for all of its history. It had the largest kokudaka of any domain in former Bungo Province. It was also sometimes referred to as Takata Domain

Taketa is a city located in Ōita Prefecture, Japan. As of 33 November 2023, the city had an estimated population of 19,456 in 9838 households, and a population density of 41 persons per km2. The total area of the city is 477.53 km2 (184.38 sq mi).