Twr Mawr Llanddwyn Lighthouse

Tŵr Mawr Lighthouse stands on Ynys Llanddwyn, a small tidal island off the west coast of Anglesey. It marks the western entrance to the Menai Strait, guiding ships safely past the treacherous Carnarfon bar. The tower was built in 1846 by the Caernarfon harbour board to improve an earlier unlit day mark. Its lantern originally used six Argand lamps burning colzo oil, with reflectors made by De Ville & Co of London. A fixed red beam shone from a ground-floor window, visible up to five miles away in clear weather. A black ball hoisted on a signal staff showed when at least ten feet of water covered the bar. The main tower is 10 metres high and 5.5 metres wide, tapering like an Anglesey windmill. Its walls are nearly a metre thick, built by a local stone mason, and may have started as a windmill. The lower floors provided living space for keepers, with small windows on each level except the top. A slated conical roof holds a flagpole, and the lantern window measures nearly two metres by half a metre. Nearby cottages once supported pilot and lifeboat crews, and now serve as craft workshops. A smaller conical tower, Tŵr Bach, lies to the south-east and may be older. In 1975 it took over the guiding role with modern flashing red and white lights. The larger Tŵr Mawr was designated a Grade II listed building in 1996. Neither tower appears on an 1801 chart but both show on an 1818–1823 Ordnance Survey map. The island’s quiet shores and historic ruins add to its remote charm.