Endemic to Inaccessible Island in the Tristan Archipelago in the isolated south Atlantic, it is the smallest extant flightless bird in the world.

The Inaccessible Island rail's taxonomic affinities and origin were a long-standing mystery; in 2018 its closest relative was identified as the South American dot-winged crake, and it was decided that both species are best classified in the genus Laterallus.

[3][4][5] The Inaccessible Island rail has brown plumage, black bill and feet, and adults have a red eye.

It occupies most habitats on Inaccessible Island, from the beaches to the central plateau, feeding on a variety of small invertebrates and also some plant matter.

Its adaptations to living on a tiny island at high densities include low base metabolic rates, small clutch sizes, and flightlessness.

The species is nevertheless considered vulnerable by the International Union for Conservation of Nature (IUCN), due to its single small population, which would be threatened by the accidental introduction of mammalian predators such as rats or cats.

[2] Prior to its collection it had been assumed by Thomson that the species was close to the other "island hens" known in the Atlantic, possibly a gallinule,[6] but on examination Lowe felt "compelled to refer it to a new genus".

[7][10] Land bridges were commonly invoked to explain biogeographical distribution patterns before the development and acceptance of plate tectonics.

Lowe thought that its closest relatives may have been black crake of Africa, or perhaps an early offshoot of the genus Porphyrio (swamphens), a conclusion based mostly on similarities of plumage.

In particular he suggested it was part of a pro-Rallus group that included the Indian Ocean genus Dryolimnas, and the Australasian Lewinia.

The Ascension crake (Mundia elpenor) and the Saint Helena swamphen (Aphanocrex podarces) were once considered congeners of A. rogersi.

The Ascension crake disappeared some time before 1700 but was briefly mentioned and described by traveller and hobby naturalist Peter Mundy in 1656.

Both the Ascension crake and the Saint Helena swamphen became extinct due to predation by introduced species, mainly cats and rats.

[3] The Inaccessible Island rail is the smallest living flightless bird in the world, measuring 13 to 15.5 cm (5.1–6.1 in).

This in turn would favour energy conservation by the rails, resulting in small body size, low BMR and flightlessness.

[19] The island is 14 km2 (5.4 sq mi) in area and has a temperate wet oceanic climate with high rainfall, limited sunshine and persistent westerly winds.

[21] It will also forage among boulders on the beaches, but has not been found in the short dry grasses on the cinder cones (the scientists making the observations cautioned that this does not mean that they never use the habitat).

The territories in the tussock grass habitats around Blenden Hall, where the population densities are highest, extend to 100–400 m2 (1,100–4,300 sq ft).

On meeting, confrontations start with loud trills or twittering, then birds may face off, standing very close to each other and displaying ritually with their heads lowered and their bills pointed towards the ground.

[21] The foraging method used by the Inaccessible Island rail is slow and deliberate and has been compared to that of a mouse, and the bird occupies a similar ecological niche.

There are a few reports of other material being used as lining, such as the leaves of introduced Malus domestica (apple) or Salix babylonica (willow).

[21] Adults are rarely preyed upon, but the mortality of chicks is high and predation by Tristan thrushes is a major cause of death.

[19] Two species of chewing lice have been found on Inaccessible Island rails, Pscudomenopon scopulacorne and Rallicola (Parricola) zumpti.

[1] Fires of tussock grass, which were recorded in 1872 and 1909, are assumed to have killed large numbers of rails, but have not occurred since.

Other suggestions for securing this species' future include increased education on biosecurity for the local community,[1] and potentially setting up a captive population.