History / 25 October 2013

The Great South Wall & Poolbeg Lighthouse

Dublin Bay  had a long history  of troublesome sandbars obstructing the entrance to Dublin Port and was also subject to frequent squalls and stormy conditions. To improve the situation, in 1716, the Ballast Office commenced construction of an embankment from Ringsend along the north aspect of the South Bull sand bank. The first piles of what was to become the South Bull Wall were driven in 1716 with major work beginning in 1717.  The Piles, as The Great South Wall was then known, were completed in 1730 to 1731. Construction involved the driving of long thick oak piles into the boulder clay of Dublin Bay. These piles were anchored by baskets of gravel. Dublin Port PoolbegA stone wall linking The Piles to the quays, The Ballast Office Wall, was completed in 1756. It soon became necessary however  to strengthen the walls with massive granite blocks taken across Dublin Bay on barges from the quarries in Dalkey.

By 1795 the wall was completed and was 32 feet thick at the base, and 28 feet at the top. At the end of the wall an island of masonry was laid down on which Poolbeg Lighthouse was built. The lighthouse was ready in 1768 before construction of the wall finally finished and initially operated on candlepower, reputedly the first in the world to do so but changed to oil in 1786. It was re-designed and re-built in 1820. The lighthouse is painted red to indicate ‘port side’ for ships entering Dublin Bay and North Bull lighthouse (on the other side of the bay) is painted green to indicate it is ‘starboard’.

Historically, the Ordnance Survey Ireland used the low water mark of the spring tide on the 8th April 1837 at the Poolbeg Lighthouse as a standard height for all its maps, a practice which continued up until 1958.


Poolbeg Lighthouse, now fully automated, is managed by Dublin Port Company . The Great South Wall on which Poolbeg Lighthouse stands, extends from Ringsend over 4km out to sea. It was the world’s longest sea-wall at the time of it’s construction and remains one of the longest to this day in Europe.

If you’re looking for a beautiful walk by the sea why not try the Great South Wall walk out to Poolbeg Lighthouse? With free parking at the end of Pigeon House Road and the beginning of South Wall it’s very easy to get to. The walk out and back takes around 40 mins and the reward when you reach the Lighthouse is the really stunning views in every direction. You’d never know what ships you may see arriving at, or leaving Dublin Port.



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