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Friday 1 December 2023 Dublin: 2°C
going underground

Underground Ireland: our country's hidden structures

A host of architectural and archaeological gems lie beneath your feet – we’ve taken a closer look at some of them…

IT’S AMAZING WHAT you can uncover when you do a little digging – and Ireland’s terrain is no exception.

To show that beauty isn’t only skin-deep, we’ve taken a look at some the country’s hidden and underground structures to see what gems lie beneath our feet.


A souterrain is a type of underground structure associated with the Iron Age which are thought to have been used as food stores or hiding places.

A notable example was excavated at Newtownbalregan, County Louth, in recent years after it was discovered during a road-building programme. It had been demolished during the Medieval period, possibly in order to prevent it from being used as a base to attack Dundalk. When contemporary archaeologists explored the intact tunnel discovered leading into the hillside; they became the first people to see inside for 600 years.

Frescati, Blackrock

Frescati House in Blackrock was an estate built for the family of the Provost of Trinity College Dublin, John Hely, in 1739 and enjoyed a rich history before its demolition in the 1980s – when a shopping centre was built in its place.

A tunnel, situated under what is now the shopping centre’s car park, was built in order to carry seawater to the estate. The waterway, nicknamed the Frescati stream, emerges at Blackrock Park but its entrance is now blocked off – and its exact location remains a secret.

James Street, Dublin

A pedestrian tunnel runs beneath James Street – one of Dublin’s oldest street – in order to connect the Guinness brewery on either side of the street.

Project Manager at the Guinness Brewery, Gerry Gallagin, waves to a colleague at one end of the Old Passenger Tunnel. Picture by: Haydn West/PA Archive/Press Association Images

The Gogginshill Tunnel

The Gogginshill Tunnel in Co Cork was carved out of rock beneath the village of Ballinhassig between February 1850 and December 1851 by 300 men. The tunnel formed part of the Cork, Bandon and South Coast Railway, and allowed Ballinhassig station to open in August 1849.

The train station finally closed in April 1961 and today the tunnel, which runs for 828 metres, is the longest abandoned tunnel in the Republic of Ireland.

Tunnel, Ballymore

A tunnel constructed in 1852 linked the Ards estate in Co Kildare to St John’s Church of Ireland. The lady of the house, Lady Isabella Tasca Stewart-Bam, commissioned the structure to allow her to travel to church without falling under the gaze of nearby peasants. As you do.

Image by Ross via Creative Commons.

Merrion Square Park, Dublin

A grass-covered hump at the corner of Fitzwilliam Street Lower in Merrion Square Park is not an unusual landscape feature but the covered entrance to a WWII air raid shelter, which links several tunnels.

Underground tunnel, Trinity College Dublin

TCD’s Lecky Library, located on the two lower floors of the university’s Arts Building, is linked physically to the Berkeley Library by an underground tunnel which was opened to users in the autumn of 1995.

Provost John Kearney (1799 – 1806) suggested building tunnels to connect Trinity with the old parliament building across the street – now owned by Bank of Ireland – but his request was refused by the government.

Kearney’s influence, as current Provost Patrick Pendergrast recently pointed out, was apparently not as strong as that of his great-great-great grand nephew: Barack Obama.

Image: Philip Halling via Creative Commons

Casino Marino

The Casino Marino in Dublin, designed as a pleasure house for James Caulfield the 1st Earl of Charemont in the 18th century, has no fewer than eight tunnels leading out from the building – one of which is a mile long.

The longest tunnel connected the garden retreat to the main living house and was used as a passageway for servants – so they could come and go without spoiling the view.

Photo: Sasko Lazarov/Photocall Ireland

Do you know of other underground Irish gems? Let us know in the comments below…

Read: Archaeologist brings Ireland’s heritage to life in new audio guide>

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