# List of islands of County Mayo

This articles lists the islands of County Mayo, the mainland of which is part of the island of Ireland. Included in this list are named offshore and freshwater islands as recorded by Ordnance Survey Ireland or the Placenames Database of Ireland. Additionally, areas of ecological significance related to both offshore and freshwater islands, designated by the National Parks and Wildlife Service, are also listed.
Although County Mayo has hundreds of offshore and freshwater islands, only a handful of islands and island groups are large enough to be distinguishable on a typical map of the county, namely Achill Island, Clare Island and Inishturk, along with the island clusters of Duvillaun, Inishkea, Clew Bay and the major loughs. There are over 100 islands which are greater than 10 acres (4.0 ha) in area. The largest island is Achill, which extends to 148 km$^2$ (37,000 acres), making it Ireland's largest offshore island.
Due to its abundance of bays, inlets and offshore islands, Mayo is reputed to have the longest coastline of any county in Ireland, at 1,168 km (726 mi) or approximately 21% of the total coastline of the State.
The geology and geomorphology of the county and its islands is among the most varied and complex in Ireland. Islands such as those at Clew Bay are low-lying, formed when rising sea levels drowned a vast field of drumlins, while others like Clare Island and Achill are characterised by mountains and towering sea-cliffs, of which Croaghaun are the third-highest in Europe, at 688 m (2,257 ft)
The bedrock geology of the islands is broadly divided into two groups. Those north of Clew Bay such as Achill and the islands off the Mullet Peninsula are generally of ancient Dalradian age, similar to County Donegal and the Grampian Highlands. Inishglora contains some of the oldest rocks in Ireland, at 1.75 billion years old. Further south, the islands are much more diverse. Clare island alone is composed of Cambrian, Ordovician, Silurian and Carboniferous terranes sutured together. Geologically, the Clew Bay islands themselves are the youngest in the county, formed during the Lower Carboniferous about 350 million years ago.
The county's offshore islands - and islands off the west coast of Ireland generally - developed their own distinct culture and traditions stretching back centuries. Records from the 1841 Census show that 47 of County Mayo's offshore islands were inhabited, with a combined population of approximately 10,000. The Great Famine resulted in widespread or total depopulation of the islands. Towards the end of the 19th century the population of the larger islands began to recover somewhat, only to be set back by emigration following independence as the Irish government initially encouraged the evacuation of the islands due to the cost of providing services to them, further hastening the decline.
Today, the islands are recognised by the State as an integral part of Ireland's national heritage, preserving the remnants of a unique aspect of Irish culture. The remaining inhabited islands receive support and funding through the Department of Culture, Heritage and the Gaeltacht. As of the 2016 Census, there are 2,700 people living on 14 of the county's offshore islands (of which 2,440 live on Achill), accounting for 1.87% of the county's population.

## Islands of Mayo by population
### Demographics

The 2016 census records 14 offshore islands as having a usually resident population. Achill has been connected to the mainland via bridge since 1887, making Clare Island the county's most populous unconnected island, with 159 inhabitants as of 2016. This makes Clare Island the fifth-most populous unconnected island in Ireland, after the three Aran Islands off Galway and Arranmore off County Donegal.
Mayo County Council is responsible for the governance of the islands, and islanders are entitled to certain benefits and exemptions, such as lower motor tax rates. The islands also receive funding from the Department of Culture, Heritage and the Gaeltacht, as several offshore islands along with much of northwest Mayo are recognised Gaeltacht areas.
As many as 47 offshore islands had permanent populations prior to the Great Famine. Communities had resided on these islands for generations, and their remains can still be seen to this day through the villages, stone walls and lazybeds which they left behind. By the end of the 19th century most of the county's islands had been deserted. In contrast, Achill benefitted from a bridge to the mainland which allowed the population to temporarily rebound, reaching its all-time peak in 1911.
Emigration from the islands continued into the 20th-century as traditional industries such as fishing and textiles were unable to provide an attractive, or in many cases adequate, income to young islanders. In recent times, the islands have become a popular tourist destination and depend heavily on the tourism and hospitality sector. Their population swells during the summer months, particularly on Achill and Clare. Popular activities include surfing, sailing, island-hopping in Clew Bay, spiritual retreats and eco-tourism.
The following table shows population trends for the fourteen currently inhabited islands as of the last census. The overall trend is a continuing decline in the population of Mayo's offshore islands, which is currently at a historic low. The county as a whole was one of just three in Ireland to record a population decrease between 2011 and 2016. The population of Mayo during this time decreased by 0.2%, whereas the population of the islands fell by 5.3%. Although the overall population fell during this time, four previously uninhabited islands received new residents, including Achillbeg, which had been uninhabited since 1965.

### Currently inhabited islands

| Rank | Island | Barony | Population | Population | Population | Population |
| Rank | Island | Barony | 2016 | 2011 | 1841 | Peak Population (if not 1841) |
| 1 | Achill | Burrishoole | 2,440 | 2,569 | 4,901 | 5,260 (1911) |
| 2 | Clare | Murrisk | 159 | 168 | 1,615 | |
| 3 | Inishturk | Murrisk | 51 | 53 | 577 | |
| 4 | Inis Bigil | Erris | 18 | 25 | 67 | 162 (1926) |
| 5 | Collanmore | Burrishoole | 7 | 4 | 213 | 215 (1851) |
| 6 | Inishnakillew | Burrishoole | 6 | 7 | 126 | |
| 7 | Inishlyre | Burrishoole | 4 | 4 | 113 | 122 (1851) |
| 8 | Clynish | Burrishoole | 4 | 4 | 87 | |
| 9 | Inish Turk Beg | Burrishoole | 4 | 10 | 57 | |
| 10 | Duvillaun More | Erris | 2 | 2 | 31 | |
| 11 | Collanbeg | Burrishoole | 2 | 0 | 4 | 9 (1861) |
| 12 | Achillbeg | Burrishoole | 1 | 0 | 178 | |
| 13 | Inishkea North | Burrishoole | 1 | 0 | 155 | |
| 14 | Rosbarnagh | Burrishoole | 1 | 0 | 42 | |
| | Total | | 2,700 | 2,846 | 8,166 | |
| | Change | | -5.3% | -65.2% | - | |

### Formerly inhabited islands

| Island | Barony | Population | Population | Population |
| Island | Barony | 1841 | Peak Population (if not 1841) | Year Abandoned |
| Rosmore Island | Burrishoole | 133 | | |
| Moynish More | Burrishoole | 99 | | 1881-1891 |
| Island More | Burrishoole | 88 | | |
| Rosturk Island | Burrishoole | 64 | | |
| Inishkea South | Erris | 62 | | 1934 |
| Inishdaff | Burrishoole | 57 | | |
| Inishgowla South | Burrishoole | 52 | | |
| Inishtubbrid | Burrishoole | 42 | | |
| Knockycahillaun | Burrishoole | 41 | | |
| Inishcottle | Burrishoole | 40 | 45 (1911) | 2011-2016 |
| Derrinish | Burrishoole | 40 | | |
| Inishquirk | Burrishoole | 37 | | |
| Inisheeny | Burrishoole | 36 | | |
| Annagh Islands | Erris | 33 | | 1851 |
| Illanataggart | Burrishoole | 33 | | |
| Inishgort | Burrishoole | 32 | 35 (1871) | 2006-2011 |
| Crovinish | Burrishoole | 32 | | |
| Inishoo | Burrishoole | 29 | | |
| Bartragh Island | Tirawley | 28 | | 1951 |
| Inisherkin | Burrishoole | 28 | | |
| Inishgowla | Burrishoole | 28 | | |
| Inishnacross | Burrishoole | 27 | | |
| Inishraher | Burrishoole | 25 | | |
| Inishturlin | Burrishoole | 25 | | |
| Inishkeel | Burrishoole | 23 | | |
| Inishbee | Burrishoole | 20 | | |
| Inishglora | Erris | 16 | | |
| Eagle Island | Erris | 15 | 22 (1861) | 1988 |
| Dorinish | Burrishoole | 13 | 15 (1871) | 1901 |
| Inishbobunnan | Burrishoole | 13 | | |
| Inishilra | Burrishoole | 12 | | |
| Inishcooa | Burrishoole | 6 | | |
| Barranagh Island | Erris | 0 | 1 (1874) | late 1800s |
| Blackrock Island | Erris | 0 | 15 (1881) | 1974 |
| Roman Island | Burrishoole | 0 | 36 (1911) | 1966-1971 |
| | Total | 1,229 | | |

## Islands of Mayo by area
### Larger islands

With the exception of Achill, County Mayo's islands are generally small in size, with only 13 larger than 100 acres (40 ha) and 3 larger than 1,000 acres (400 ha). There are numerous offshore islands in the 10 to 100 acre range, along with at least 15 freshwater islands larger than 10 acres, the largest of which is Illannaglashy on Lough Conn at 82 acres (33 ha).
The one hundred largest islands in the county are listed below. "F" designates a freshwater island.
| Island | Irish name | Archipelago / Location | Area (Acres) | Highest Point |
| Achill | Acaill | Achill Islands | 36,572 | 688 m (2,257 ft) |
| Clare | Oileán Chliara | Clew Bay | 4,053 | 462 m (1,516 ft) |
| Inishturk | Inis Toirc | Atlantic Islands | 1,620 | 191 m (627 ft) |
| Inishbiggle | Inis Bigil | Achill Islands | 637 | 34 m (112 ft) |
| Annagh Island | Oileán an Eanaigh | Achill Islands | 627 | 23 m (75 ft) |
| Inishkea North | Inis Gé Thuaidh | Inishkea Islands | 574 | 24 m (79 ft) |
| Bartragh Island | An Bheartrach | Killala Bay | 477 | 26 m (85 ft) |
| Inishkea South | Inis Gé Theas | Inishkea Islands | 389 | 72 m (236 ft) |
| Achillbeg | Acaill Bheag | Achill Islands | 331 | 110 m (360 ft) |
| Collanmore Island | Collainn Mhór | Clew Bay | 199 | 53 m (174 ft) |
| Duvillaun More | Dubhoileán Mór | Duvillaun Islands | 177 | 63 m (207 ft) |
| Caher Island | Cathair na Naomh | Atlantic Islands | 130 | 61 m (200 ft) |
| Rosmore Island | An Ros Mór | Newport Bay | 116 | 28 m (92 ft) |
| Illannaglashy (F) | Oileán na Glaise | Lough Conn | 82 | 27 m (89 ft) |
| Clynish | Claínis | Clew Bay | 81 | 42 m (138 ft) |
| Island More | An tOileán Mór | Clew Bay | 78 | 42 m (138 ft) |
| Barranagh Island | Oileán Bearanach | Blacksod Bay | 74 | 7 m (23 ft) |
| Inish Turk Beg | Inis Toirc Bheag | Clew Bay | 64 | 53 m (174 ft) |
| Inishnakillew | Inis na Coilleadh | Newport Bay | 64 | 27 m (89 ft) |
| Moynish More | Maínis Mór | Clew Bay | 62 | 37 m (121 ft) |
| Inishglora | Inis Gluaire | Atlantic Islands | 60 | 22 m (72 ft) |
| Inishbee | Inis Bí | Newport Bay | 56 | 29 m (95 ft) |
| Duvillaun Beg | Dubhoileán Beag | Duvillaun Islands | 53 | 14 m (46 ft) |
| Rosbarnagh Island | Oileán Ros Bairneach | Newport Bay | 53 | 37 m (121 ft) |
| Inishlyre | Inis Ladhair | Dorinish Harbour | 52 | 26 m (85 ft) |
| Annagh Island East | An tEanach Thoir | Wesport Bay | 48 | 9 m (30 ft) |
| Annagh Island (F) | Oileán an Eanaigh | Lough Conn | 45 | 23 m (75 ft) |
| Inishtubbrid | Inis Tiobrad | Newport Bay | 41 | 28 m (92 ft) |
| Inishdaff | Inis Damh | Newport Bay | 40 | 31 m (102 ft) |
| Inishower (F) | Inis Odhar | Furnace Lough | 36 | 16 m (52 ft) |
| Knockycahillaun | Cnoc Uí Chathaláin | Clew Bay | 35 | 36 m (118 ft) |
| Carrigeenamore (F) | An Carraigín Mór | Lough Mask | 35 | 22 m (72 ft) |
| Bleanmore Island | An Bhléan Mhór | Corraun Peninsula | 34 | 14 m (46 ft) |
| Rosturk Island | Ros Toirc | Newport Bay | 34 | 24 m (79 ft) |
| Inishgowla | Inis Gabhla | Newport Bay | 33 | 28 m (92 ft) |
| Inishdegil More | Inis Téigil Mór | Atlantic Islands | 32 | 12 m (39 ft) |
| Inishkeeragh | Inis Caorach | Atlantic Islands | 32 | 17 m (56 ft) |
| Kid Island | Oileán Mionnán | Broadhaven Bay | 32 | 86 m (282 ft) |
| Illanataggart | Oileán an tSagairt | Clew Bay | 32 | 28 m (92 ft) |
| Carrickmoylenacurhoga | Carraig Bhéal na gCaróg | Inishkea Islands | 32 | 14 m (46 ft) |
| Inishquirk | Inis Coirce | Newport Bay | 32 | 44 m (144 ft) |
| Inishgort | Inis Goirt | Clew Bay | 31 | 29 m (95 ft) |
| Inishsherkin | Inis Earcáin | Newport Bay | 31 | 30 m (98 ft) |
| Inishkeel | Inis Caol | Newport Bay | 30 | 27 m (89 ft) |
| Crovinish | Croibhinis | Dorinish Harbour | 29 | 23 m (75 ft) |
| Derrinish | Dairinis | Newport Bay | 29 | 21 m (69 ft) |
| Inishraher | Inis Raithir | Westport Bay | 29 | 33 m (108 ft) |
| Inishlaughil | Inis Leamhchoille | Newport Bay | 28 | 45 m (148 ft) |
| Bartraw Island | An Bheartrach | Westport Bay | 28 | 13 m (43 ft) |
| Inishgowla South | Inis Gabhla Theas | Westport Bay | 28 | 20 m (66 ft) |
| Inishnacross | Inis na Croise | Newport Bay | 27 | 36 m (118 ft) |
| Inisheeny | Inis Aonaigh | Westport Bay | 27 | 22 m (72 ft) |
| Muckinish | Muicinis | Newport Bay | 26 | 37 m (121 ft) |
| Annaghroe Island (F) | An tEanach Rua | Lough Conn | 25 | 18 m (59 ft) |
| Glassillan | An Glasoileán | Achill Island | 25 | 23 m (75 ft) |
| Inishcottle | Inis Cotail | Newport Bay | 25 | 26 m (85 ft) |
| Inishgleasty (F) | Inis Gléasta | Lough Mask | 24 | 37 m (121 ft) |
| Inishbobunnan | Inis Bó Bonnán | Newport Bay | 24 | 31 m (102 ft) |
| Eagle Island | Oileán sa Tuaidh | Atlantic Islands | 23 | 60 m (200 ft) |
| Roeillaun | Rua-oileán | Clew Bay | 23 | 33 m (108 ft) |
| Inishloy | Inis Láí | Newport Bay | 23 | 10 m (33 ft) |
| Inishcooa | Inis Cua | Newport Bay | 23 | 27 m (89 ft) |
| Long Island (F) | An tOileán Fada | Lough Mask | 22 | 25 m (82 ft) |
| Rabbit Island | Oileán Bhríde | Clew Bay | 21 | 22 m (72 ft) |
| Inishrobe (F) | Inis Róba | Lough Mask | 21 | 30 m (98 ft) |
| Inishturlin | Inis Tuirlinge | Newport Bay | 21 | 27 m (89 ft) |
| Inishcuill | Inis Coill | Newport Bay | 21 | 28 m (92 ft) |
| Derreens Island (F) | An Doirín | Carrowmore Lake | 20 | 8 m (26 ft) |
| Dorinish | Deoirinis | Clew Bay | 20 | 30 m (98 ft) |
| Roslynagh | Ros Laighneach | Clew Bay | 18 | 33 m (108 ft) |
| Illannambraher East | Oileán na mBráthar Thoir | Clew Bay | 18 | 28 m (92 ft) |
| Carrickawilt | Carraig an Mhoilt | Inishkea Islands | 18 | 9 m (30 ft) |
| Inishoght (F) | Inis Uicht | Lough Mask | 18 | 25 m (82 ft) |
| Collanbeg Island | Collainn Bheag | Clew Bay | 17 | 25 m (82 ft) |
| Inishoo | Inis Uamha | Clew Bay | 17 | 32 m (105 ft) |
| Annagh Island West | An tEanach Thiar | Westport Bay | 17 | 11 m (36 ft) |
| Inishdaweel | Inis Dá Mhaol | Clew Bay | 16 | 38 m (125 ft) |
| Carrigee | Carraig Aodha | Inishkea Islands | 16 | 15 m (49 ft) |
| River Island (F) | Oileán na hAbhann | Lough Mask | 16 | 13 m (43 ft) |
| Saints Island (F) | Inis Na Naomh | Lough Mask | 16 | 30 m (98 ft) |
| Inishdurra (F) | Inis Dura | Lough Mask | 16 | 32 m (105 ft) |
| Inishleague | Inis Liag | Wesport Bay | 16 | 24 m (79 ft) |
| Baunros More | Bánros Mór | Killala Bay | 15 | 13 m (43 ft) |
| Inishdalla | Inis Deala | Atlantic Islands | 15 | 27 m (89 ft) |
| Inishdasky | Inis Teasctha | Clew Bay | 15 | 30 m (98 ft) |
| Annaghteige Island (F) | Eanach Thaidhg | Lough Conn | 15 | 27 m (89 ft) |
| Rabbit Island | Oileán Bhríde | Newport Bay | 15 | 28 m (92 ft) |
| Illandavuck | Oileán Dhabhaic | Atlantic Islands | 14 | 56 m (184 ft) |
| Conors Island (F) | Oileán Chonchúir | Lough Carra | 14 | 20 m (66 ft) |
| Inishfesh | Inis Feise | Clew Bay | 13 | 10 m (33 ft) |
| Inishaghoo | Inis Achadh | Achill Islands | 13 | 20 m (66 ft) |
| Carrigeenagur Island (F) | Carraigín na gCorr | Lough Mask | 13 | 23 m (75 ft) |
| Pig Island (F) | Oileán na Muice | Lough Mask | 13 | 28 m (92 ft) |
| Illannambraher West | Oileán na mBráthar Thiar | Clew Bay | 12 | 25 m (82 ft) |
| Inishkee | Inis Caoich | Clew Bay | 12 | 14 m (46 ft) |
| Inishdoonver | Inis Dúnmhar | Clew Bay | 12 | 25 m (82 ft) |
| Lambs Island (F) | Oileán na nUan | Lough Mask | 12 | 11 m (36 ft) |
| Devenish Island (F) | Daimhinis | Lough Mask | 12 | 30 m (98 ft) |
| Annagh Island Middle | An tEanach Lár | Westport Bay | 12 | 7 m (23 ft) |
| Goose Island | Inis na nGé | Killala Bay | 12 | 12 m (39 ft) |

## Smaller offshore islands

County Mayo has hundreds of smaller islands and islets. Most of the county's offshore islands are located in Clew Bay, with smaller clusters located around the Achill archipelago, the west and south coasts of the Mullet Peninsula, and Blacksod Bay. The list below is not exhaustive, and includes named offshore islands that are either extensive (typically greater than 2 acres in area) or in someway locally significant or identifiable.
Unlike the above list, this list is in alphabetical order and does not include freshwater islands.
| Island | Irish name | Archipelago / Location |
| Annagh Island | Oileán an Eanaigh | Mullet Peninsula |
| Ardillaun | Ardoileán | Killala Bay |
| Attimonbeg | Áth Tíomáin Beag | Killala Bay |
| Baunros Beg | Bánros Beag | Killala Bay |
| Baunros More | Bánros Mór | Killala Bay |
| Beetle Island North | Oileán an tSindile Thuaidh | Clew Bay |
| Beetle Island South | Oileán an tSindile Theas | Clew Bay |
| Bills Rocks | Carraig Bill | Atlantic Islands |
| Blackrock Island | An Tor | Atlantic Islands |
| Buddagh | An Chailleach | Benwee Head |
| Calf Island | Oileán an Ghamhna | Clew Bay |
| Calf Island | Oileán an Ghamhna | Killala Bay |
| Camel Island | Oileán Camall | Newport Bay |
| Carrickduff | An Charraig Dhubh | Mullet Peninsula |
| Carrickduff | An Charraig Dhubh | North Mayo Coast |
| Carrickhesk | Carraig Sheisc | Mullet Peninsula |
| Carricknaronty | Carraig na Rónta | Atlantic Islands |
| Carricknaronty North | Carraig na Rónta Thuaidh | Mullet Peninsula |
| Carricknaweeloge | Carraig na bhFaoileog | Mullet Peninsula |
| Carrigeenglass North | An Carraigín Glas Thuaidh | Clew Bay |
| Cone Island | Oileán an Chuain | Mullet Peninsula |
| Corillan | Corroileán | Westport Bay |
| Carrigeenaveagh | Carraigín na bhFiach | Clew Bay |
| Cregnarullah | Sceir na Roilleach | Mullet Peninsula |
| Cross Rock | An Charraig Dhubh | Mullet Peninsula |
| Doonvinalla | An Dúna | Benwee Head |
| Doonbristy Island | Dún Briste | North Mayo Coast |
| Dooneen Island | An Dúnín | Uggool Beach |
| Finnaun Island | Fionnán | Westport Bay |
| Forillan | Foroileán | Westport Bay |
| Freaghillan | Fraochoileán | Killala Bay |
| Freaghillan East | Fraochoileán Thoir | Newport Bay |
| Freaghillanluggagh | Fraochoileán Logach | Newport Bay |
| Glassillaun | Glasoileán | North Mayo Coast |
| Green Island | An tOileán Glas | Westport Bay |
| Green Island | An tOileán Glas | Killala Bay |
| Heath Island | Oileán Fraoigh | Corraun Peninsula |
| Horse Island | Oileán na gCapall | North Mayo Coast |
| Illancroagh | Oileán Cruaiche | Corraun Peninsula |
| Illanleamnahelty | Oileán Léim na hEilte | Atlantic Islands |
| Illanmaster | Oileán Máistir | North Mayo Coast |
| Illanmaw | Má-oileán | Clew Bay |
| Illannaconney | Oileán an Chonnaidh | Clew Bay |
| Illannakanoge | Oileán na gCánóg | North Mayo Coast |
| Illannamona | Oileán na Móna | Achill Islands |
| Illaunatee | Oileán an Tí | Clew Bay |
| Illaunroe | An tOileán Rua | Clew Bay |
| Inishacrick | Inis an Chnoic | Clew Bay |
| Inishbollog | Inis Bolg | Clew Bay |
| Inishcannon | Inis Ceannann | Newport Bay |
| Inishcoragh | Inis Córach | Newport Bay |
| Inishcorky | Inis Corcaí | Clew Bay |
| Inishdaugh | Inis Deách | Clew Bay |
| Inishdeash Beg | Inis Déise Beag | Clew Bay |
| Inishdeash More | Inis Déise Mór | Clew Bay |
| Inishderry | Inis Doire | Mullet Peninsula |
| Inishilra | Inis Iolra | Clew Bay |
| Inishimmel | Inis Imill | Westport Bay |
| Inishlaghan | Inis Lachan | Clew Bay |
| Inishlim | Inis Loim | Clew Bay |
| Inishmolt | Inis Molt | Newport Bay |
| Kid Island East | Oileán na Meannán | Newport Bay |
| Mauherillan | Máthairoileán | Newport Bay |
| Money Beg | An Muine Bheag | Clew Bay |
| Moynish Beg | Maínis Beag | Clew Bay |
| Mweelaun | Mhaoilinne | Atlantic Islands |
| Pig Island | Oileán na Muice | North Mayo Coast |
| Quinsheen Island | Cuinsín | Clew Bay |
| Roeillan | Rua-oileán | Achill Islands |
| Rosnambraher | Ros na mBráthar | Newport Bay |
| Sloe Island | Oileán na nAirní | Westport Bay |
| The Stags | Na Stacaí | Benwee Head |
| Toghercloheen | Barr na Spince | North Mayo Coast |
| Torduff | An Tor Dubh | North Mayo Coast |

## Freshwater islands

There are numerous large loughs within the county, containing hundreds of small freshwater islands. Lough Mask in southern Mayo is the largest lough in the county. At 83 km$^2$ (21,000 acres) it is the 6th-largest lough in Ireland (as well as the 6th-largest in Britain and Ireland). Further south, Lough Corrib is the 2nd-largest lough in Ireland; however, only a small portion of this lough is located within the county.
Illannaglashy, on Lough Conn, is the largest freshwater island in the county, at 82 acres (33 ha) in area. Freshwater islands have played an important role in the county's history and host an abundance of castles, monasteries, church ruins and unspoiled woodlands.

### Lough Mask

* Note: The vast majority of Lough Mask is within County Mayo, with a small southern portion of the lough located in County Galway. This list only includes islands which are within the boundary of County Mayo.
* Aghinish
* Bed Island
* Bilberry Island
* Black Island
* Black Island
* Board Island
* Carrigeen Island
* Carrigeen Middle
* Carrigeenabreana
* Carrigeenagur Island
* Carrigeenamore
* Carrigeenavilla
* Carrigeenaweelaun
* Carrigeenbaun
* Carrigeenbunnahown
* Carrigeendany Islands
* Carrigeenduree
* Carrigeenfair Island
* Carrigeenkeelagh
* Carrigeenmauntrasna
* Carrigeennagool
* Carrigeennalogh
* Carrigeennasassonagh
* Carrigeenowen
* Carrigeenshangorman
* Castle Hag
* Cow Island
* Dash Island
* Devenish Island
* Doran Islands
* Goat Island
* Green Island
* Gull Island
* Flag Island
* Heath Island
* Illan Columbkille
* Illanboe Beg
* Illanboe More
* Illandawaur
* Ingon Island
* Inishangan
* Inishdurra
* Inishgleasty
* Inishoght
* Inishowenlackboy
* Inishrobe
* Kid Island
* Lackboy
* Lamb Island
* Long Island
* Long Islands
* Lusteen Beg
* Lusteen More
* Nut Island
* Oak Island
* Pig Island
* Rams Island
* Rialisk
* Ringolden
* River Island
* Saints Island
* Seerillaun
* Shangorman
* Shrub Island
* Thick Island
* Whiteland Island

### Lough Carra

* Ballycally Island
* Bird Island
* Bonnianillish Island
* Bush Island
* Carrigeennagat Island
* Castle Island
* Castlehag Island
* Church Island
* Conors Island
* Cow Islands
* Crane Island
* Creevagh Island
* Deer Island
* Derrinrush Island
* Derrynafresha Island
* Doonbeg Island North
* Doonbeg Island South
* Gleneary Island
* Hog Island
* Horse Island
* Illanatrim
* Kiln Island
* Lady's Island
* Lakeview Island
* Leamnahye Island
* Long Island
* Mearing Island
* Otter Island
* Otter Island
* Otter Islands
* Pleasure Island
* Priest Island
* Rat Island
* Stare Island
* Stony Island

### Lough Corrib

* Note: The vast majority of Lough Corrib is within County Galway, with a small northern portion of the lough located in County Mayo. This list only includes islands which are within the boundary of County Mayo.
* Abbots Rock
* Ballycurrin Island
* Bartragh Island
* Bertragh Islands
* Blackderry Island
* Blackderry Rock
* Bushy Island
* Camillaun
* Carrigeen
* Castletown Rock
* Cornelian Islands
* Crow Islands
* Dog Islands
* Easter Island
* Flower Island
* Gibbs Islands
* Grass Island
* Green Island
* Green Island East
* Holy Island
* Inishkeeragh Island
* Island Morris
* Kilmore
* Kilmorebeg
* Matthew Island
* Mine Island
* Mucky Island
* Oak Island
* Prison Islands
* Rabbit Island
* Red Island
* Salmon Island
* Salmon Point Island
* Sloe Island
* Whiskey Island

### Lough Conn

* Annagh Island
* Annaghroe Island
* Annaghteige Island
* Bears Island
* Burnt Island
* Carnaweelan Island
* Castle Island
* Chain Island
* Cliff Island
* Coarse Island
* Cragh Islands
* Creeve Island
* Freaghillan
* Illanaghty
* Illanaloughaun
* Illanbeg
* Illannaglashy
* Inishlee Island
* Longford Island
* Loosky Island
* Rinard Island
* Rocky Island
* Roe Island
* Sandy Island

### Smaller lakes
#### Lough Cullin

* Griffins Island
* Illanboy
* Illaner
* Illangub
* Illanneill
* Illanulque

#### Lough Beltra

* Bush Island
* Coarse Island
* Islandmore
* Low Island
* Tree Island

#### Carrowmore Lake

* Atlavally Island
* Derreens Island
* Gortmore Island
* Muingerroon Island

#### Furnace Lough

* Illanroe
* Inishower
* Saints Island

#### Islandeady Lough

* Note: Despite being a small lough, Islandeady had three sizeable islands, at 38, 21 and 20 acres respectively. However, due to the lowering of waterlevels in the 20th century the three islands are now peninsulas.
* Illanlteige East
* Illanteige West
* Islandeady

## Monastic islands

Six islands within County Mayo have had a dedicated monastery or abbey established on them. Four of these are offshore, and two of these are freshwater islands. They are listed below:
* Church Island Monastery (F)
* Clare Island Abbey
* Duvillaun Monastery
* Inishkea North Monastery
* Inishglora Monastery
* Partry Monastery (F)
In addition to the above sites, many more islands within the county have been used for religious purposes. The ruins of old churches and cemeteries can be found scattered across such islands.

## Biodiversity

Many of the county's offshore and freshwater islands are designated as areas of ecological significance and are protected both at national and European level. Mayo's offshore islands are a haven for wildlife and biodiversity, supporting hundreds of species of bird, fish and marine mammal, as well as unique vegetation. Five of the county's major inland lakes (along with their islands) are also protected, those being Lough Mask, Lough Conn, Lough Cullin, Lough Carra and Carrowmore Lake.
The biodiversity of the islands is protected under the following designations. There is overlap across designations, as different designations apply to different species, e.g. the Duvillaun Islands are an SAC, SPA and proposed NHA.
* Special Area of Conservation (SAC) - These are prime wildlife conservation areas in the country, considered to be important on a European as well as Irish level.
* Special Protection Area (SPA) - Classified under the EU Birds Directive for the protection of endangered species of wild birds.
* Natural Heritage Area (NHA) - This is an area considered important for the habitats present or which holds species of plants and animals whose habitat needs protection.
The following areas of ecological significance are located either on or adjacent to County Mayo's offshore islands. The five major inland lakes listed as SPAs are also included, and are shown in italics in the list below.

### Special areas of conservation

* Mullet/Blacksod Bay Complex
* West Connacht Coast
* Erris Head
* Inishkea Islands
* Duvillaun Islands
* Broadhaven Bay
* Killala Bay/Moy Estuary
* Croaghaun/Slievemore
* Achill Head
* Keel Machair/Menaun Cliffs
* Doogort Machair/Lough Doo
* Clew Bay Complex
* Corraun Plateau
* Lough Gall Bog
* Clare Island Cliffs

### Special protection areas

Italics indicates that the SPA is an inland lake
* Blacksod Bay/Broadhaven Bay
* Inishglora and Inishkeeragh
* Inishkea Islands
* Duvillaun Islands
* Stags of Broad Haven
* Illanmaster
* Killala Bay/Moy Estuary
* Doogort Machair
* Bills Rocks
* Clare Island
* Mullet Peninsula
* Termoncarragh Lake & Annagh Machair
* Lough Mask
* Lough Conn & Lough Cullin
* Lough Carra
* Carrowmore Lake

### Natural heritage areas

* Tullaghan Bay & Bog
* Doogort East Bog
* Sraheens Bog

### Proposed natural heritage areas

* Killala Bay/Moy Estuary
* Glenamoy Bog Complex
* Stags Of Broadhaven
* Broadhaven Bay
* Erris Head
* Eagle Island
* Mullet/Blacksod Bay Complex
* Inishglora & Inishkeeragh
* Inishkea Islands
* Duvillaun Islands
* Croaghaun/Slievemore
* Doogort Machair/Lough Doo
* Inishgalloon
* Keel Machair/Menaun Cliffs
* Corraun Plateau
* Lough Gall Bog
* Bills Rocks
* Clare Island
* Clew Bay Complex
* Mweelaun Island
* Caher Island
* Ballybeg Island
* Inishturk
* Inishdalla
* Frehill Island
* Inishdegil Islands

## Island index

* Achill Island
* Clare Island
* Inishturk
* Inishkea North
* Inishkea South
* Achillbeg
* Annagh Island
* Caher Island
* Barranagh Island
* Inishbiggle
* Eagle Island
* Inishglora