The Glenveagh Castle Gardens are part of Glenveagh National Park in the north west of County Donegal. The site occupied by the castle and gardens was formerly wild mountain moorland, with construction of the castle beginning in 1869 and the gardens in the mid 1880s. The two major elements of the garden, the Pleasure Gardens and the Walled Garden, were built in the late 1880s. The gardens, which were constructed for Cornelia Adair, still retain their original Victorian layout.

From the late 1950s through to the early 1980s, the design and layout of the garden were developed to include the Gothic Orangery, the Italian Terrace, the Tuscan Garden and the development of the plant collection.

Today, Glenveagh is well known for its rich collection of trees and shrubs specialising in southern hemisphere species and a diverse rhododendron collection. Displays of rhododendrons are at their best from late March to the end of May.

Access to the gardens is from dawn to dusk all year round. Admission to the park, including the gardens, is free.