It is ringed by a reef flat, with a beach ridge of coral rock and rubble surrounding the rim, rising to five metres above sea level.

Treeless, McKean harbours seven herbaceous species of plants, and the world's largest nesting population of lesser frigatebird (Fregata ariel) with up to 85,000 birds.

[3] Only a small cover of Halimeda was observed while carpeting soft corals (Sinularia and Lobophytum) occupied 10% of the bottom of the lagoon.

Henry Barber, of the ship Arthur, while en route from Botany Bay, New South Wales to the northwest coast of America.

[7] The island was reported and visited by a number of ships in the years following, including the whaleship Japan in 1830 (under Capt.

Shubael Chase), Captain Worth (1832) who mistook it for Onotoa and an unknown whaleship in 1834, who named it "Wigram's Island".

[8] It was renamed McKean Island and mapped by commander Charles Wilkes of the US Exploring Expedition on August 19, 1840, after a member of his crew.

However, Arthur Island remained suspected and "in need of confirmation" until at least 1871, when it was listed in Findlay's Directory, using the charts of cartographer John Arrowsmith.

When the White Swallow left, the Aspasia of Mystic, and Bowditch of New London were loading at McKean's Island, the only one worked at present.

[13] In addition to natural history expeditions, it was visited in October 1989 by TIGHAR when it was surveyed as a possible landing site of Amelia Earhart.