Some 120 hectares (300 acres) of the lands of Derrynane, together with Derrynane House, make up Derrynane National Historic Park. The House was officially opened as a museum commemorating Daniel O’Connell by President Eamon De Valera in August 1967 and the surrounding park was officially declared open by President Cearbhall Ó Dálaigh in August 1975 to mark the 200th anniversary of O’Connell’s birth.
The original house, built around 1720 by Captain John O' Connell. The grounds have many gate lodges summer houses and follys.
Although Derrynane was never one of the great estates of Kerry, the grounds around the house were developed with care by several generations of the O’Connell family. Plantations and garden walks were laid out in the eighteenth and nineteenth centuries.
The winters are very mild, so that, like other well-known gardens of Kerry and west Cork such as Rossdohan, Ilnacullin, frost-sensitive trees and shrubs flourish. For this reason, as part of the National Botanical Collection, plants from South America have been established here.