Crocnafarragh is located in the north-west of Ireland in Co. Donegal. The property is a vast mountainous wilderness covering 2605 hectares. The site supports herds of Red Deer, Golden Eagles and Red Grouse. The property forms an integral part of Glenveagh National Park. It is the Western most section of the park which is also made up of the Glenveagh estate and the Southern slopes of Mount Errigal. The site is owned by An Taisce (since 1968) and managed by the staff of Glenveagh National Park. The site is a nature reserve of international importance. This is reflected by its multiple desginations for nature conservtion under Irish and European law, namely the Derryveagh and Glendowan Mountains Special Protection Area and the Cloghernagore Bog and Glenveagh National Park Special Area of Conservation and Natural Heritage Area.
The site is named after the highest mountain Crocnafarragh which is located at the centre of the property. The peak of which measures 517m offers a panoramic view of the surrounding countryside as far south as the Sligo coastline on a fine day. To the North you can see the impressive volcanic cone of Mount Errigal (751m), the highest point in Co. Donegal, to the west Gweedore Bay and the Atlantic Ocean and to the east the Poision Glen, the Derryveagh Mountains and Slieve Sneacht within the Glenveagh estate.
The geology of the site consists of rolling Donegal highlands with numerous small mountains, cliffs, lakes, rivers and numerous waterfalls. Several impressive boulders or erratics sit on elevated parts of the property where they have been since they were left behind by receding glaciers during the last Ice Age. The most significant lakes of site include Lough Nacung Lower and Dunlewy Lough in Gweedore, Lough Nabrackbaddy, Glentoran Lough, Red Water Lough and Lough Attirive. Numerous rivers flow off the site including the Glentoran River and the Owenator Rivers. The freshwater flowing off the property provides importnat drinking water sources for the surrounding population.
The property holds a rich diversity of habitats and landscape features, including mountains, exposed rock and scree, blanket bogs, dry, wet and alpine heath, upland grassland, wet grassland, molinia meadows, rivers, lakes, scrub and woodland with certain sections of the property form part of the Cloghernagore Bog And Glenveagh National Park Special Area of Conservation (SAC) and proposed Natural Heritage Area (pNHA), Site Code (002047). Crocnafarragh also contains the Derryveagh and Glendowan Mountains SPA, Site Code (004039). The majority of the site at Crocnafarragh is blanket bog, where the vegetation is relatively uniform and typically dominated by Purple Moor-Grass (Molinia caerulea) or Fionnán in Irish, Heather (Calluna vulgaris), Black Bog-Rush (Schoenus nigricans), Deergrass (Scirpus cespitosus) and Common Cottongrass (Eriophorum angustifolium), with areas of Bog Myrtle (Myrica gale) and Bog Moss (Sphagnum) species (S. auriculatum and S. cuspidatum) occurring. The site is of great scientific and conservation value, particularly for the large areas of excellent, little-damaged blanket bog it contains, including the largest intact area of blanket bog in north-west Ireland. It also includes good quality examples of semi-natural deciduous woodland, heath, oligotrophic lakes and inland cliffs. The importance of the site is increased by the presence of a wide range of plant and animal species, including many rare or threatened Red Data Book species, and several that are listed on Annex II of the E.U. Habitats Directive or Annex I of the E.U. Birds Directive. The site is of high ornithological importance with nationally important breeding populations of five species. Of particular note is that five of the species that occur regularly are listed on Annex I of the E.U. Birds Directive, i.e. Red-throated Diver, Peregrine, Merlin, Golden Plover and Dunlin (subsp. schinzii). The site also supports herds of Red Deer (Cervus elaphus), the reintroduced Golden Eagle (Aquila chrysaetos) and Red Grouse (Lagopus lagopus). Two threatened species once synonymous with the Irish uplands.
Threats to the site include illegal turf cutting, the hunting and the poisoning of wildlife. There are a number of invasive species including Rhododendron, Japanese Knot Weed, Lodepole Pine and Gunnera in the surrounding town-lands which pose a serious threat long term.
Further information on the range on the ecological details of the property can be obtained from the National Parks and Wildlife Service