| Oka Castle | |
|---|---|
岡城 | |
| Saiki, Ōita Japan | |
 Walls of Oka Castle | |
  Oka Castle  Oka Castle | |
| Coordinates | 32°58′9.18″N 131°24′29.05″E / 32.9692167°N 131.4080694°E |
| Type | yamajiro-style Japanese castle |
| Site information | |
| Controlled by | Nakagawa clan |
| Open to the public | yes |
| Condition | Archaeological and designated national historical site; castle ruins |
| Website | Official website |
| Site history | |
| Built | c.1185 |
| Built by | Ogata Koreyoshi |
| In use | Edo period |
 | |
Oka Castle (岡城, Oka-jō) was a Sengoku to Edo period yamajiro-style Japanese castle located in the city of Taketa, Ōita Prefecture, Japan. Its ruins have been protected as a National Historic Site since 2023.[1]