Disappointingly, there is a massive quarry here now. But there was a rath, a souterrain, and a naturally rocky craggy place.
Cleena had one of her palaces in the centre of a great rock, situated about five miles from Mallow, still well known by the name of Carrig-Cleena, and there is a legend attached to it, recounted by Windele, from which Cleena's moral character appears to have been doubtful. A market or fair was held in the neighbourhood; and on these occasions she came out of her abode and carried off every good-looking young man at the fair who pleased her. It was told how a peasant one evening had seen the whole space about the rock brilliantly lighted up, the entrance door thrown open, and a fair lady standing within. Some people cultivated the ground around th rock with potatoes; but Cleena was heard within piteously wailing, as if lamenting the desecration, and the men desisted.
[...] Even Cleena had a more estimable side to her character. Some of the peasantry of the country around Carrig Cleena regard her in the light of a benefactress. In her neighbourhood no cattle die from the influence of the evil eye, nor the malignant power of the unfriendly spirits of the air. Her goodness preserves the harvest from the blights which dissipate the farmer's hopes. The peasantry are the children of her peculiar care. She often appears, disguised in thehomely garb of a peasant girl, to announce to some late wayfarer the expulsion from her dominions of invading spirits, and the consequent certainty of an abundant harvest.
The NMS record quotes 'Berry 1905' "A wild and romantic spot... a rude elevation, surrounded by a rampart of huge rocks, towering over the country round, and enclosing about two acres of very green ground" - there was a soutterrain inside the fort which was 'said locally' to connect the rocks and the fort.
The quarriers didn't get it all their own way though. This forum has someone saying "I rem as a child hearing it had a quarry and the machinery used to break down, go on fire etc. and it was blamed on Clíona, queen of the fairies and it didn't stop until a mass was said there. " and another person recalls the mass being about 30 years ago.
There are many variations on the fairy queen's name of Clíodhna. Anne Ross ('Pagan Celtic Britain') connects her with the British Rhiannon, as they both have three otherworldly birds as assistants (as you may see here and here).