Numerous passages connect the lagoon to the surrounding ocean, only a couple of which will admit even a small boat.

Like Manra, Orona is covered with coconut palms (mostly on the western side), towering 12–18 metres (39–59 ft) above the surface.

The remainder of the atoll is covered with scrub forest, herbs, and grasses, with a maximum height of 6–12 metres (20–39 ft).

[6] At inner leeward lagoon sites, coral species were identified typical of high-silt environments (e.g. Montipora efflorescens, Acropora lovelli), growing in fine calcareous silt in aggregated patches together with abundant giant clam (Tridacna).

Towards the center and windward side of the lagoon the sandy bottom became coarser with coral growth developing around dead bommies and small patch reefs.

An ancient stone marae stands on the eastern tip of the island, together with ruins of shelters, graves and other platforms.

Orona was leased in 1916 to a Captain Allen of the "Samoan Shipping and Trading Company", and became a copra plantation.

[9] British and American claims to the island ended in 1979 with the independence of Kiribati from Great Britain and the signing of the Treaty of Tarawa in which the US retains the right to re-establish a military base.