Lettermore (Irish: Leitir Móir, lit. 'great rough hillside') 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').

Historical population

Year Pop. ±% 1841 844 —     1851 661 −21.7% 1861 669 +1.2% 1871 718 +7.3% 1881 890 +24.0% 1891 832 −6.5% 1901 747 −10.2% 1911 801 +7.2% 1926 721 −10.0%	Year Pop. ±% 1936 677 −6.1% 1946 815 +20.4% 1951 843 +3.4% 1956 820 −2.7% 1961 710 −13.4% 1966 600 −15.5% 1971 604 +0.7% 1979 597 −1.2% 1981 582 −2.5%	Year Pop. ±% 1986 542 −6.9% 1991 508 −6.3% 1996 503 −1.0% 2002 497 −1.2% 2006 528 +6.2% 2011 548 +3.8% 2016 513 −6.4% 2022 542 +5.7%
Source: Central Statistics Office. "CNA17: Population by Off Shore Island, Sex and Year". CSO.ie. Retrieved 12 October 2016. Population of Inhabited Islands Off the Coast (Report). Central Statistics Office. 2023. Retrieved 29 June 2023.

• List of towns and villages in the Republic of Ireland
• Darach Ó Catháin
• Gorumna
• CLG Naomh Anna, Leitir Móir
• Fiachra Breathnach
• Seoighe Inish Bearachain
• Peigín Leitir Móir