First metal lighthouse

The first metal lighthouse was made from cast iron in 1803 by architect William Jernegan and built at the end of the pier in Swansea Harbour, West Glamorgan, UK. The iron plates used to construct the 6.1-m (20-ft) octagonal tower were cast in the nearby Neath Abbey Ironworks.

Topped by a smaller octagonal lantern, the iron lighthouse was placed on a stone plinth and stood 6.1 m (20 ft) tall and sat 8.53 m (28 ft) above the high-water line. It was originally lit by candles, though this was changed to an oil lamp in 1845. In 1878, the old structure was moved to the end of the extended wooden pier built by James Abernethy, taking its height up to 7.01 m (23 ft). Its service came to an end in 1909 when the pier was extended once again and a new lighthouse was installed.

The idea of constructing a lighthouse from cast iron was first proposed in 1799, by the Royal Navy's Captain Joseph Brodie who suggested a cast-iron lighthouse be built on Bell Rock off Scotland. However, it was decided stone would be the more durable material. The decision was borne out as the Bell Rock Lighthouse, operational since 1 February 1811, is active to this day making it the oldest offshore lighthouse.

The first metal lighthouse to be built in the Americas was the 35-m-tall (115-ft) cast-iron Morant Point Lighthouse in Jamaica (still in use today). It was prefabricated in the UK by Alexander Gorden and assembled by free African immigrants from Sierra Leone in 1841.