Inishbiggle (Irish: Inis Bigil) is a small inhabited island off the coast of Ballycroy in County Mayo. Its name in Irish means "Vigil Island".

The island is unique in that it is traditionally both a Gaeltacht and Protestant.

The island is situated between the northeast of Achill Island and the mainland, and is accessed by boat from either Doran's point at Ballycroy or Bullsmouth, Dooniver on Achill Island. The island is 2½ km x 1½ km, or 650 acres (2.6 km) in area.

The main activities are sheep and cattle farming, fishing and winkle picking. Facilities on the island included a school and a post office, both now closed.

Plans to build a cable-car link across the Bullsmouth Channel, one of the strongest currents in Europe separating the island from Achill had been under discussion since 1996, but have now been abandoned. Planning permission for the cablecar was denied by Mayo County Council on the grounds that "It would be visually obtrusive in an area of special scenic importance, that it would create traffic problems and that it would devalue houses in the vicinity."

Unpredictable currents in the channel during winter months can render the island inaccessible, even though the passage during fair weather is about ten minutes in the traditional boat, the currach. Emergency access is by helicopter.

The table below reports data on Inishbiggle's population taken from Discover the Islands of Ireland (Alex Ritsema, Collins Press, 1999) and the Census of Ireland.

At the end of 2023 the population had dropped to 8 people.

Historical population

Year Pop. ±% 1841 67 —     1851 61 −9.0% 1861 0 −100.0% 1871 154 —     1881 171 +11.0% 1891 135 −21.1% 1901 135 +0.0% 1911 149 +10.4% 1926 162 +8.7%	Year Pop. ±% 1936 157 −3.1% 1946 106 −32.5% 1951 123 +16.0% 1956 116 −5.7% 1961 113 −2.6% 1966 103 −8.8% 1971 112 +8.7% 1979 97 −13.4% 1981 89 −8.2%	Year Pop. ±% 1986 69 −22.5% 1991 51 −26.1% 1996 48 −5.9% 2002 39 −18.8% 2006 24 −38.5% 2011 25 +4.2% 2016 18 −28.0% 2022 12 −33.3%
Source: Central Statistics Office. "CNA17: Population by Off Shore Island, Sex and Year". irishislands.info. Retrieved 12 October 2016.

• Nevins

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  Potato Labour Scandal 1971

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  Ulster Scots dialects

• Discover Ireland - Inishbiggle