Designed by David and Thomas Stevenson it cost just over £8k to buy the land and cover construction and establishment costs. The tower cost just under £4k and the lantern – which had a power of 9,000 candles – cost £620. The foghorn, completed the following year in 1881, was set up to send a blast of 5 secs every 40 secs.

The lighthouse, with its perimeter wall enclosing over 2 acres of land and numerous outhouses and living quarters for 3 keepers, was completed several weeks ahead of the 18 month schedule.

Castletown residents celebrated the completion of the lighthouse in December 1880 with hundreds of onlookers gathered on the pier. A bonfire was lit and rockets fired in to the air to celebrate the occasion. The Castletown brass band played and at 6.00pm the long-awaited light cast its first powerful beam out for 15 miles every 5 seconds. The lighthouse worked well until 1933 when a fire broke out in the lightroom, destroying the lamp. A new light was acquired at a cost of £561, and a further upgrade took place in 1937 giving the light a power of 200,000 candles. It currently has two white flashes every thirty seconds.