This light is located at the end of the West Pier of Dun Laoghaire Harbour. It and the East Pier Light were built to guide into the harbour ships that were waiting to get into the Port of Dublin. In 1909 a fog horn was added to this station at the request of the London North-Western Railway. In 1949 the Principal Keeper from the East Pier Light moved into the dwelling here when the East Pier Light became a three-keeper station.