Situated near the north west tip of Wales, the tiny islet known as South Stack Rock lies separated from Holyhead Island by 30 metres of turbulent sea, surging to and fro in continuous motion. The coastline from the breakwater and around the south western shore is made of large granite cliffs rising sheer from the sea to 60 metres.

South Stack Lighthouse was first envisaged in 1665 when a petition for a patent to erect the lighthouse was presented to Charles II. The patent was not granted and it was not until 9th February 1809 that the first light appeared to mark the rock. The lighthouse, erected at a cost of £12,000, was designed by Daniel Alexander and originally fitted with Argand oil lamps and reflectors. Around 1840 a railway was installed by means of which a lantern with a subsidiary light could be lowered down the cliff to sea level, when fog obscured the main light.

On Tuesday 25th October 1859 it is said that the most severe storm of the century occurred. It became known as the 'Royal Charter' gale, and on that and the following day over 200 vessels were either driven ashore or totally wrecked with the loss of 800 lives. The steamship ROYAL CHARTER was among these, and she sunk within yards of help with the loss of almost 500 passengers and crew. On that evening Assistant Keeper Jack Jones had been making his way across the iron bridge on to South Stack so that he could join the Principal Keeper Henry Bowen, already on duty. A rock was swept from the cliff by the strong wind, fell and struck Jones on the head. Covered in blood, almost senseless with concussion, he dragged himself up the gale lashed path. Feebly he cried out for help, then, head in hands, he lay unable to move any further. Henry Bowen found him in the same place on the Wednesday morning, groaning and unable to move, his hair matted with blood. Jack Jones died three weeks later of a compound fracture of the skull.

In the mid 1870's the lantern and lighting apparatus was replaced by a new lantern. No records are available of the light source at this time but it was probably a pressurised multiwick oil lamp. In 1909 an early form of incandescent light was installed and in 1927 this was replaced by a more modern form of incandescent mantle burner. The station was electrified in 1938.

On 12th September, 1984, the lighthouse was automated and the keepers withdrawn. The light and fog signal are now remotely controlled and monitored from the Trinity House Operational Control Centre in Harwich, Essex.

The chasm between the mainland and the rock was at first traversed by a hempen cable 21 metres above sea level, along which a sliding basket was drawn carrying a passenger or stores. This system was replaced in 1828 by an iron suspension bridge 1.5 metres wide and again in 1964 by an aluminium bridge. The present footbridge was completed in mid-1997. Grants totalling £182,000 were received from the Welsh Development Agency to fund the structure which was designed and built by Laings/Mott Macdonald. The landward approach to the bridge is by descending 400 steps cut into the cliff face.

With the completion of the footbridge the island and the lighthouse were reopened to visitors.