As shipping losses mounted around An Sgeir Mhòr ‘the big skerry’, the Northern Lighthouse Board decided to build a lighthouse there. Eleven miles offshore, battered by huge waves, and ringed by menacing rocks, it was a daunting task. They turned to the twenty-nine-year-old Alan Stevenson. His father, Robert, was no stranger to this sort of challenge, being the Board’s engineer and designer of the Bell Rock Lighthouse.

In 1836 the Board bought fifty acres of Hynish Farm from the Duke of Argyll. Work on the shore station began the following year. The Barracks were built to accommodate the workforce, with workshops set up by the shore. The surrounding fields provided grazing for the project’s cows and horses.

For seven years, stonemasons chiselled 4,300 granite blocks by hand. Every stone was different, and they had to be dressed and checked against a wooden mould to within 1 mm. Most stones took between 50 to 80 hours to make, although a particularly intricate one on the eighty-fourth course took 320 hours.

Two nearby quarries provided material for the shore station and the bottom three courses of the lighthouse itself. But the Lewisian gneiss rock proved difficult to fashion to the required specification, and Stevenson turned to pink granite from the Ross of Mull to complete the task. 

The Hynish pier was the first such on Tiree. However, the Atlantic swell sweeping around the headland was so bad that a box harbour had to be built to protect the lighthouse tender. The harbour had a tendency to fill up with sand. To solve this problem, Stevenson diverted a stream on Ben Hynish down to a reservoir, using this water to flush the sand out at low tide. He also set wooden booms at the harbour entrance.

Skerryvore Lighthouse, described by Robert Louis Stevenson, Alan’s nephew, as ‘the noblest of all extant deep sea lights’, exhibited for the first time in 1844. Despite the challenges of the site, there had been no fatalities.

For fifty years, the Upper Square was home to four lighthouse keepers and their families. But after Dubh Artach lighthouse was built off Islay in 1872, the Northern Lighthouse Board moved the keepers to the shore station on Erraid on the Ross of Mull.