It was built in 1785 and forms part of the Downhill Demesne. The demesne was formerly part of the estate of Frederick, 4th Earl of Bristol, who served as the Church of Ireland Lord Bishop of Derry from 1768 until 1803. It was Lord Bristol - popularly known as 'the Earl-Bishop' - who had the 'temple' built. Constructed as a library and modelled from the Temple of Vesta in the Forum Romanum in Rome, it is dedicated to the memory of Bishop Lord Bristol's cousin Frideswide Mussenden.
Over the years the erosion of the cliff face at Downhill has brought Mussenden Temple ever closer to the edge, and in 1997 The National Trust carried out cliff stabilisation work to prevent the loss of the building.
The inscription around the building reads, "Suave, mari magno turbantibus aequora ventis e terra magnum alterius spectare laborem." "Tis pleasant, safely to behold from shore / The troubled sailor, and hear the tempests roar." The quotation is from Lucretius De Rerum Natura, 2.1-2
Now part of The National Trust property of Downhill Estate & Mussenden Temple, the grounds encompassing Mussenden Temple, and its manor house (Downhill Castle) are open to the public all year, from dawn to dusk. The temple itself is open on certain days, and admission is free. The 'Temple' offers views westwards over Downhill Strand towards Magilligan Point and on across to Inishowen in County Donegal; and to the east, Castlerock beach towards Portstewart, Portrush and Fair Head.
The temple obtained a licence to hold civil wedding ceremonies in 2007.
The nearest station is Castlerock railway station.
- Examples of recent rockfalls from basalt cliffs in Northern Ireland, Peter Wilson and Alana Cunningham, School of Environmental Sciences, University of Ulster at Coleraine, Irish Geography, Volume 36(2), 2003, 170-177, retrieved 18 September 2009
- Mussenden Temple and Downhill Demesne, National Trust
- Weddings at Mussenden Temple, National Trust