Ahuahu/Great Mercury Island is privately owned and public access is allowed (excluding residential sites and the planted pine forest).

Sea levels began to rise 7,000 years ago, after which the islands separated from the rest of New Zealand.

[6] The island is owned by Michael Fay and David Richwhite, two prominent New Zealand businessmen.

[7] U2's lead singer Bono and guitarist The Edge stayed on the island during U2's Vertigo concerts in Auckland in November 2006.

[8] In 2014, Fay and Richwhite, in partnership with the Department of Conservation, successfully undertook an eradication program to remove kiore, ship rats and cats from the island.

[13] The smaller islands in the group have been identified as an Important Bird Area by BirdLife International because they provide nesting sites for up to 3000 breeding pairs of Pycroft's petrels.