[citation needed] Manus reaches an elevation of 700 m (2,300 ft) and is volcanic in origin and probably broke through the ocean's surface in the late Miocene, 8–10 million years ago.

There is little tourism, although the seas are attractive to divers, including Jean-Michel Cousteau who spent time on nearby Wuvulu Island in the 1970s.

[2] The 58.5 km2 (22.6 sq mi) Ndrolowa Wildlife Management Area was created in March 1985 south of Lorengau on Manus Island and contains both terrestrial and marine regions.

Birds found mainly but not exclusively on the Admiralty Islands include Melanesian megapode (Megapodius eremita), yellow-bibbed fruit-dove (Ptilinopus solomonensis), yellowish imperial-pigeon (Ducula subflavescens), pied cuckoo-dove (Reinwardtoena browni), Meek's pygmy parrot (Micropsitta meeki), black-headed white-eye (Zosterops hypoxanthus) and ebony myzomela (Myzomela pammelaena).

[citation needed] Mammals found only here or on nearby island groups include the large fruit bats, Admiralty flying-fox (Pteropus admiralitatum), Andersen's naked-backed fruit bat (Dobsonia anderseni) and Seri's sheathtail-bat (Emballonura serii) while the two pure-endemics are Admiralty Island cuscus (Spilocuscus kraemeri) and a local mosaic-tailed rat (Melomys matambuai).

This early society appears to have cultivated taro, and to have deliberately introduced wild animals from New Guinea such as bandicoots and large rats.

[6] The Lapita culture arose around 3,500 years ago, and its extent ranged from the Admiralty Islands to Tonga and Samoa.

[6] The first European to visit the islands was the Spanish navigator Álvaro de Saavedra when trying to return from Tidore to New Spain in the summer of 1528.

In November 1914, the islands were occupied by troops of the Australian Naval and Military Expeditionary Force landed from the SS Siar.