This mound has got some good folklore, according to the accounts in 'Sketch of the Civil and Traditional History of Caithness' by James Tait Calder (1861) cp53.
Torgaeus gives an account of a remarkable prodigy which was seen [..] in Caithness. On Christmas-day (the day of the battle [of Clontarf] a man, named Daraddus, saw a number of persons on horseback ride at full speed towards a small hill, near which he dwelt, and seemingly enter into it. He was led by curiosity to approach the spot, when, looking through an opening in the side of the hillock, he observed twelve gigantic figures, resembling women, employed in weaving a web. As they wove, they sang a mournful song or dirge descriptive of the battle in Ireland, in which they foretold the death of King Brian, and that of the Earl of Orkney. When they had finished their task, they tore the web into twelve pieces. Each took her own portion, and once more mounting their horses, six galloped to the south, and six to the north.
[..] The scene of this extraordinary legend is supposed to be a knoll or hillock, in the parish of Olrig, called Sysa, which has been particularly celebrated, from time immemorial, as a favourite haunt of witches and fairies...
Before 'agricultural improvements' Sysa 'posessed some features of interest' and sounds suitably magical:
On gaining the top from the north, you saw the side fronting the south shaped into a beautiful green hollow, having a gentle slope downwards. This hollow contained a spring of delicious water, clear as crystal; and in the summer season, the sward around it was of the richest green, thickly sprinkled with wild flowers, and contrasting strongly with the brown and stunted herbage of the surrounding moor.
The writer also goes on to describe another story, at great length, called 'The Piper of the Windy Ha'.' I will try to summarise it:
Many years ago, there was a young man called Peter Waters, and he'd stopped at the well of Sysa to have a drink after driving his cattle onto the common. It was a beautiful warm day in June and after he lay back for a snooze, it wasn't long before he was fast asleep. It was nearly sunset when he was woken up by someone shaking his shoulder. A beautiful girl stood next to him, dressed in green, with blue eyes and golden ringlets. Peter was a shy lad and nearly ran off in embarrassment and fright, but the girl smiled at him so kindly that he stayed put. She said in a voice as soft and clear as a silver bell, "You're a very interesting boy, and I've come to make a man of you."
Unsurprisingly Peter took this to mean something quite forward, but she laughed and explained that she would help him make his fortune. She mysteriously produced a set of pipes inlaid with silver, and a gold-embossed bible. "You must choose between these - the pipe will make you the best musician in Scotland, and the book the most popular preacher."
After a quick ponder, Peter chose the pipes, and was delighted to discover that he could play them perfectly, despite never having tried the instrument before. "Some cattle that were grazing hard by lifted their heads from the ground the moment they heard the first notes of the tune, and kept flinging and capering about in the most extraordinary manner."[!]
Before they parted, the lady said, "There is one condition attached to your gift - seven years from this day, at the exact same hour of the evening, you must meet me by the well of Sysa." Peter had to swear on the fairy well that he would, and walked back over the hill of Olrig to his father's house, "Windy Ha'".
As soon as his parents saw the pipes and heard how he'd got them, they advised him to have no more to do with them - they'd come from the queen of the fairies. But Peter was so pleased with his new-found ability to play, that he performed at every party for miles around, gradually gathering a small fortune.
Eventually the seven years rolled away, and Peter felt anxious about meeting the strange lady. As the sun set he started off, and his dog started after him, but Peter sent the dog back home. It howled as it saw him disappear over the hill. No-one knows what happened to Peter at this second meeting, but he never returned to Windy Ha', and the general belief was that he'd been carried away to Fairyland.
I originally added this site because I thought it was a similarly-sounding name broch nearby. But now I discover it is something different - and what is it? In 1911 the RCAHMS thought it was natural. But it had a reputation for being hollow and artificial, as you see from the story. In 1965 the OS said confidently that it was 'undoubtedly natural', but come the NMRS visit of 1995, there are mentioned 'slight depressions in the surface [which] may indicate chambers'. So perhaps opinion is swinging the other way. I can see it could well get axed as a tma site, but I think it's kind of defensible since it is a mound large in the imagination of the local people: a large 30ft high lump on the landscape, with attendant fairy folklore (the type often attached to brochs and cairns).