Owenduff / Nephin Complex SAC is a large area of relatively intact blanket bog and mountains in County Mayo. It incorporates much of the Nephin Beg mountain range. The upper slopes of the mountains have wet heath vegetation and patches of upland grassland. To the south and east, the site is bounded by coniferous plantations. The lower mountain slopes are covered with blanket bog. Wet heath is widespread and is found in mosaic and transition with the lowland blanket bog. Greenland White-fronted Goose visit in winter. Golden Plover breed here in summer and the area is a feeding ground for Merlin. This site is one of the best and largest examples of intact blanket bog in Ireland.

Bellacorick Bog Complex SAC is a low-lying undulating plain in County Mayo. It contains some of the most extensive areas of lowland blanket bog remaining in Ireland. Good examples of wet heath vegetation occur occasionally on sloping ground and on elevated mounds of mineral soil that are throughout the lowland blanket bog-covered plains.

Mweelrea / Sheeffry / Erriff Complex SAC is a large area of blanket bog in south Mayo. Lowland blanket bog was once more extensive but is now fragmented by coniferous forestry. Wet heath occurs in upland regions where peat depth is shallow. Dry heath occurs on sloping, well-drained peat. The patchwork of lowland blanket bogs provides a roosting area for Greenland White-fronted Goose.

Glenamoy Bog Complex SAC is situated in the extreme north-west of County Mayo. It is a prime example of the extreme oceanic form of lowland blanket bog. The bog occupies a gently undulating plain that extends to cover hill slopes in the east of the site, and north towards the sea cliffs. The region has been heavily afforested and much of the site is bounded by conifer plantations.

Carrowmore Lake Complex SAC is located north and east of Bangor Erris, in Co. Mayo. The site is of considerable ecological value, primarily for its extensive, intact blanket bog, which has a typical range of good-quality habitats, but also as a site for the very rare Marsh Saxifrage and the moss Drepanocladus vernicous.

Lough Gall Bog SAC is on a low-lying peninsula on the western side of Bellacragher Bay, a sheltered sea inlet in north-west Co. Mayo. It is a relatively small area of lowland blanket bog, with a good diversity of features typical of the habitat, i.e. hummock and hollow areas, pool systems, streams, flushes, lakes, swallow-holes, islands and natural drains.

Slieve Fyagh Bog SAC is located about 6 km north-east of Bangor in Co. Mayo. It is bounded on the north by the Glenamoy River, on the east and west by forestry plantations, and on the south by the Glencullin River. Slieve Fyagh itself is a plateau of shales and sandstone rocks, reaching an elevation of approximately 300 m.