The area is roughly circular, and connects with the rest of the island at a relatively narrow neck, which runs between Kintra and Port Ellen. Its high point is Beinn Mhòr (202 metres (663 ft)) in the south. The Oa had a population of 800 people in 1830, but became deserted due to the Highland Clearances.
The area around the memorial is an RSPB nature reserve, where chough, golden eagles, corn crakes, and sea birds can be seen. 1,931 hectares (4,770 acres) have been designated as a Special Protection Area for the protection of the chough.
- Media related to The Oa at Wikimedia Commons