It is separated from the mainland in the west by Apuau Channel and in the north and east by Waitātā Reach.

[1] The island comprises two main parts: the bulk of the island lies to the west and is oriented roughly northeast to southwest; a smaller spur, connected by a narrow 1-kilometre long isthmus, lies to the east.

[2] Military installations were built on the island during World War II.

Remains of the old gun emplacements and range finding equipment can be seen from the track, close to the island's northernmost point.

Thanks to the efforts of conservationist Don Merton, kākāpō was introduced onto the predator-free island in 1974.