The southern end of Auckland Island broadens to a width of 26 km (16 mi) where a narrow channel, known as Carnley Harbour or the Adams Straits, separates it from the roughly triangular Adams Island (area approximately 100 km2 or 39 sq mi), which is even more mountainous, reaching a height of 705 m (2,313 ft) at Mount Dick.

[1] The channel is the remnant of the crater of an extinct volcano, with Adams Island, and the southern part of Auckland Island forming the crater rim.

Two large indentations, Bolton's Bay and Fly Harbour, are the most prominent features of the island's south coast, both in the south east.

[3] Thus, its fauna, which may be representative of pre-human times, differs significantly from that of many other islands in the archipelago including the main Auckland Island, which still has introduced pigs, cats and mice.

This article about the geography of New Zealand's outlying islands is a stub.