[1] The Oki Islands are volcanic in origin, and are the exposed eroded summits of two massive stratovolcanoes dating approximately 5 million years ago to the Tertiary and Quaternary periods.

Dōgo to the east is the largest island in area, and has the highest elevation, Mount Daimanji, at 608 metres (1,995 ft) above sea level.

For administrative purposes, the Japanese government officially considers the disputed islet of Liancourt Rocks (Dokdo or Takeshima) to be a part of the town of Okinoshima on Dōgo.

The islands have been recognised as an Important Bird Area (IBA) by BirdLife International because they support populations of Japanese wood pigeons.

[4] The Oki Islands have been inhabited since the Japanese Paleolithic era, and numerous artifacts from the Jōmon, Yayoi and Kofun periods have been found by archaeologists, indicating continuous human occupation and activity.

The islands were organized as Oki Province under the Ritsuryō reforms in the latter half of the seventh century, and the name “Oki-no-kuni” appears on wooden markers found in the imperial capital of Nara.