Tearaght Island or Inishtearaght (Irish: An Tiaracht, meaning "the westerly") is an uninhabited steep rocky island west of the Dingle Peninsula.
At longitude 10° 39.7' Tearaght is the westernmost of the Blasket Islands, and thus the westernmost island of Ireland. It is also one of the westernmost points in Europe after Iceland, and Azores. However, there are some exposed rocks further west: Tearaght Rocks, Tearaght Rocks West (10° 41.0'), and Foze Rocks (10° 41.3').An Tiaracht is about a kilometre from east to west, and 500 metres (1,600 feet) from north to south. The island is divided into two sections, a larger eastern part (200 metres (660 feet) high) and a western part that rises to 116 metres (381 feet). A narrow neck of rock, with a natural tunnel through it, joins the two parts.
Like the other Blasket Islands, Tiaracht holds large numbers of seabirds, with internationally important populations of Manx shearwater and European storm-petrel. Leach's storm-petrels have also been found there (but not proved to be breeding) in recent years. The number of auks, especially puffins, has apparently fluctuated greatly, though early records are not always reliable.
A lighthouse was established on the island in 1870, and automated in 1988. The lighthouse, maintained by the Commissioners of Irish Lights, has a tower 17 metres (56 feet) high and the focal height is at 84 metres (276 feet) above sea level, it has a range of 19 nautical miles (35 kilometres; 22 miles). The light was served by the steepest funicular rail track in Europe from 1913 until automation.