According to Séamas Ó Murchú, the current official name, Inis Oírr, was brought into use by the Ordnance Survey Ireland.

The terrain of the island is composed of limestone pavements with crisscrossing cracks known as "grikes", leaving isolated rocks called "clints".

[citation needed] The effects of the last glacial period (the Midlandian) are most in evidence, with the island overrun by ice during this glaciation.

Pre-existing lines of weakness in the rock (vertical joints) contribute to the formation of extensive fissures separated by clints (flat pavement-like slabs).

[6] The grikes (crevices) provide moist shelter, thus supporting a wide range of plants including dwarf shrubs.

But when the limestone pavement is covered by a thin layer of soil, patches of grass are seen, interspersed with plants like the gentian and orchids.

Notable insects present include the butterfly the pearl-bordered fritillary (Boloria euphrosyne), brown hairstreak (Thecla betulae), marsh fritillary (Euphydryas aurinia) and wood white (Leptidea sinapis); the moths, the burren green (Calamia tridens), Irish annulet (Gnophos dumetata) and transparent burnet (Zygaena purpuralis); and the hoverfly Doros profuges.

The ruins of Teampall Chaomháin in Inisheer cemetery have to be uncovered annually as the floor of it is well below the level of the sand.

[8][9] The cargo vessel MV Plassy, which was shipwrecked off Inis Oírr on 8 March 1960,[10] has since been thrown above the high tide mark at Carraig na Finise on the island by strong Atlantic waves.

[10] On the night of the wrecking, a young boy on the island spotted the grounded ship and ran to the village, where the alarm was raised.

[citation needed] In addition, many school pupils from the mainland come to the island to learn Irish in an environment where it is a living language in the local college, Coláiste Laichtín during the months of June, July and August.

[16] Inisheer is also the name of a well-known slow air written by Thomas Walsh from Dublin, after a visit to the island in the 1970s.