[2] Most of the smaller islets lie in a small arc south of North Brother, with the largest being only some one hectare in area.

[3] The Māori name for the group, Ngāwhatu-kai-ponu, literally means "the eyes that witnessed" and according to tradition it refers to the eyeballs of the giant octopus, Te Wheke-a-Muturangi, that Kupe battled.

[4][5][6] During Captain James Cook's first visit to the area, HMS Endeavour was very nearly wrecked on the Brothers, as a lack of wind and strong tide drove the ship towards the rocks.

[8] When a lighthouse was erected on Mana Island to serve Cook Strait comment was made in the Marlborough Press that despite the expense it would have been better to have put one on the Brothers.

[12] In 1872 the barque City of Newcastle was lost because the Captain mistook the Mana Island light for the entrance to Wellington Harbour.

A further upgrade occurred in August 1990 when the light was switched to a 50 watt tungsten halogen solar powered beacon and fully automated.

North Brother Island is a sanctuary for a rare reptile subspecies, the Brothers Island tuatara (Sphenodon punctatus guntheri), and is the type locality for a rare beetle species, the Cook Strait click beetle (Amychus granulatus), although the latter is possibly extinct there now.