Ireland operates two distinct protected area systems. The Republic of Ireland administers six national parks under the National Parks and Wildlife Service, a division of the Department of Housing, Local Government and Heritage. Northern Ireland, as part of the United Kingdom, maintains separate designations including Areas of Outstanding Natural Beauty and nature reserves under the Department of Agriculture, Environment and Rural Affairs. The Republic's national parks collectively cover approximately 62,000 hectares. Northern Ireland does not use the national park designation despite the Giant's Causeway being managed as a UNESCO World Heritage Site by the National Trust.
Killarney National Park, established in 1932, was Ireland's first national park. The Muckross Estate, donated by Senator Arthur Vincent and his parents-in-law Mr. and Mrs. William Bowers Bourn of California, formed the initial 4,000-hectare core. The park now encompasses 10,289 hectares in County Kerry. The Lower Lake, Middle Lake, and Upper Lake form the Lakes of Killarney system within the park boundaries. MacGillycuddy's Reeks, Ireland's highest mountain range, rises along the park's western edge, with Carrauntoohil reaching 1,038 meters. The park protects the only remaining native herd of red deer in Ireland, descended from populations that survived the last Ice Age. Oak woodlands along the lake shores represent remnants of the temperate rainforest that once covered much of Ireland. Killarney fern, a species dating to the Tertiary period, grows on rocks near the waterfalls. Muckross House, a Victorian mansion completed in 1843, operates as a museum within the park. The 15th-century Ross Castle stands on the Lower Lake shore. Torc Waterfall drops 20 meters over a rock face accessible by a one-kilometer path from the main road.
Connemara National Park covers 2,957 hectares in County Galway. The park opened in 1980 after the state purchased the Letterfrack estate. Four of the Twelve Bens mountain range fall within park boundaries: Benbaun at 729 meters, Bencullagh, Benbrack, and Muckanaght. Blanket bog covers approximately 1,200 hectares of the park. These bogs began forming 2,500 years ago when deforestation and climate change created waterlogged conditions. Diamond Hill rises 442 meters from the visitor center, with a trail system offering a four-kilometer loop or a seven-kilometer circuit. Connemara ponies, a breed documented since the 16th century, graze within the park though the herd is not wild. Red grouse and peregrine falcons nest in the uplands. The Ellis Wood contains oak and birch forest regenerating since grazing ended. The park acquired an additional 967 hectares in 2000 when the Lissoughter estate was purchased.
Glenveagh National Park protects 16,548 hectares in County Donegal. The park was created in 1984 when Henry McIlhenny donated Glenveagh Estate to the Irish state. McIlhenny, a Philadelphia art collector, had purchased the property in 1937. Lough Veagh stretches 7.5 kilometers through a glacial valley that forms the park's spine. Glenveagh Castle, completed in 1873 for John George Adair, stands on the lakeshore. Adair evicted 244 tenants from the valley in 1861, creating a depopulated landscape. The gardens around the castle contain species from five continents, including Himalayan rhododendrons and Tasmanian tree ferns. A visitor center operates at the park entrance, with a shuttle bus covering the 4.5 kilometers to the castle. The park reintroduced golden eagles in 2000 through a partnership with Scottish conservationists. Twenty-four eaglets were brought from Scotland between 2001 and 2006. As of 2023, approximately seven breeding pairs occupy territory in Donegal. Red deer were introduced to Glenveagh in the 1890s, creating a non-native herd now managed through culling.
Wicklow Mountains National Park encompasses 20,483 hectares across Counties Wicklow, Dublin, and Wexford. The park was established in 1991 with the initial purchase of the Glendalough Valley. Lugnaquilla, at 925 meters, is the highest peak in the Wicklow range and the park's highest point. The Military Road, constructed by British forces between 1800 and 1809 following the 1798 Rebellion, runs through the park for approximately 30 kilometers. Blanket bog covers the upper slopes above 300 meters elevation. The Sally Gap and Wicklow Gap are mountain passes cutting through the plateau. Glendalough contains the remains of a monastic settlement founded by St. Kevin in the 6th century. The round tower at Glendalough stands 33 meters tall and was constructed between the 10th and 12th centuries. The Upper and Lower Lakes at Glendalough are glacial formations. The park does not have a single visitor center; information is available at multiple access points including Glendalough and Bahana.
Burren National Park covers 1,673 hectares in County Clare. The park opened in 1991 and consists of land purchased from individual farmers and the Office of Public Works. The Burren is a karst landscape formed from Carboniferous limestone deposited 350 million years ago when the area was beneath a tropical sea. Glaciation during the last Ice Age stripped away topsoil, exposing limestone pavement with vertical cracks called grikes and horizontal blocks called clints. Arctic-alpine plants including mountain avens and spring gentian grow alongside Mediterranean species in the temperate microclimate created by the limestone. The flowering period runs from April through August. Mullaghmore, a terraced limestone hill within the park, reaches 191 meters. Approximately 75 percent of Ireland's native plant species occur in the Burren region. Ring forts and wedge tombs dot the landscape, with Poulnabrone dolmen, a portal tomb constructed around 3200 BCE, standing two kilometers outside the park boundary. Grazing by cattle and goats prevents scrub encroachment on the limestone pavement. The park has no visitor center; access is unregulated from multiple points.
Ballycroy National Park protects 11,000 hectares of Atlantic blanket bog in County Mayo. The park was designated in 1998. The Owenduff River system drains the bog complex. The Nephin Beg mountain range rises along the eastern boundary, with Slieve Carr reaching 721 meters. Atlantic blanket bog began forming here approximately 4,000 years ago. Peat depth reaches four meters in sections. The bog remains 98 percent intact with minimal human disturbance. The Ballycroy Visitor Centre opened in 2006. Golden plover and dunlin breed on the bog during summer months. Greenland white-fronted geese overwinter in the area, arriving in October and departing in April. The Wild Nephin Wilderness, designated in 2017, extends the protected area northward by adding 11,000 hectares of state-owned forestry being returned to bog and native woodland. This wilderness designation was Ireland's first, prohibiting development and mechanized access beyond walking trails.
The Phoenix Park in Dublin covers 707 hectares, making it one of Europe's largest enclosed urban parks. The park was created in 1662 when the Duke of Ormond purchased land for a royal deer park. A wall enclosing the entire perimeter was completed in 1680. Áras an Uachtaráin, the residence of Ireland's president, occupies 0.5 square kilometers within the park. The United States ambassador's residence stands adjacent to the presidential property. Dublin Zoo, opened in 1831, operates on 28 hectares in the park's southeast section. A herd of approximately 400 fallow deer descends from the original 17th-century stock. The Wellington Monument, completed in 1861, rises 62 meters and is the tallest obelisk in Europe. Ashtown Castle, a medieval tower house, was discovered in 1986 when a Georgian structure built around it was demolished. The Phoenix Monument, erected in 1747, gave the park its name through anglicization of the Irish "fionn uisce" meaning clear water.