As this is a Gaeltact village, the Irish Leitir Móir is the official name.
Lettermore (Irish: Leitir Móir, lit.'great rough hillside')[2] is a Gaeltacht village in County Galway, Ireland. It is also the name of the island, linked by road to the mainland, on which the village sits. The main spoken language of the area is Irish.
Lettermore island is in two halves. The eastern half is known as Lettermore, while the western half is known as Lettercallow (Irish: Leitir Calaidh, lit.'rough hillside by a marshy area').[3]
^Census of Ireland, 1911: Area, Houses, and Population : Also the Ages, Civil Or Conjugal Condition, Occupations, Birthplaces, Religion, and Education of the People. United Kingdom, H.M. Stationery Office, 1912.