Glenveagh National Park, National park in County Donegal, Ireland.

Glenveagh National Park covers 170 square kilometres of the Derryveagh Mountains, including Mount Errigal and Slieve Snaght, and Lough Veagh. Glenveagh Castle stands on the lake shore with its Victorian gardens, and a visitor centre is nearby. The park contains 100 hectares of woodland, the largest being Mullangore Wood on the south-east shore of Lough Veagh.

John George Adair assembled the Glenveagh estate from parcels bought in 1857–1859 and evicted 244 tenants in April 1861. He began building Glenveagh Castle in 1870, completing it in 1873. His widow Cornelia expanded the castle and laid out the gardens, and the estate later passed to Arthur Kingsley Porter in 1929 and Henry McIlhenny in 1937. McIlhenny sold the lands to the Office of Public Works in 1975 and donated the castle and gardens in 1981; the national park opened in 1984.

Cornelia Adair laid out the castle gardens after inheriting the estate in 1885, and from 1940 Henry McIlhenny had Jim Russell redesign them and widen the plant collection. The library holds paintings by AE Russell, and guests such as Yehudi Menuhin and Greta Garbo stayed at the castle.

The park is open year-round and welcomes walking through the mountains and around the lakes. The visitor center serves as a good starting point to explore different trails and learn more about the area.

Golden eagles were absent from Ireland from 1912 until birds from Scotland were released at Glenveagh in 2000; the released pair raised their first chick in 2007 and two more in 2009. The red deer herd moves freely inside a 40 km fence, grazing the wet mountain slopes in summer and retreating to the woods around Lough Veagh in winter.