According to local folklore, Sioda Mac Namara, the head of the clan who built Quinn Abbey, came upon a beautiful horse at Cullane lake one day. These were a type of fairy animal known as water horses or kelpies. He managed to capture the horse and brought it home where he trained it and rode it for many years. But one day while Sioda was riding the horse he passed Cullane lake and the horse went wild and jumped off a rock. He returned home to the lakes fairy waters, also drowning Sioda Mac Namara. Every seven years Sioda Mac Namara and the water horse are seen rising out of the lake and riding around Kilkishen. The rock which the horse jumped off, was shown to antiquarian John Westropp some time before 1870, and a local man reputedly saw Sioda and the water horse near the lake in the 19th or 20th century.
According to local folklore, during the penal times, when Quin Abbey was closed and the monks persecuted, they hid their gold vessels under a large flag in the river. They even filled the bell with lead and flung it too into the river where it sunk. Twice men went digging for the gold vessels, once a large eel came out of the lake and attacked them and the second time two men went digging, they lifted up the flag and a woman dressed in white came at them shrieking. They ran in fear.
Another story concerning Quin abbey, is that there is supposed to be a tunnel going from the abbey to Knappogue castle. Reputedly the vessels of the Abbey were brought to the Mac Namaras in Knappogue, through the tunnell. it is also said that during penal times, it was the O’ Briens of Dromoland helped the monks escape to the mountains near Ballinruan were they slept at a well called Tobar Na Naomh.
According to local folklore, tin 1402 the 4 year old son of Macon Mac Namara, Lord Clanculein who was living in Dangan Castle, went missing. He was eventually found drowned in a pond in the garden. Macon swore that if God could bring him back to life, he would build a church. The boy came back to life on the feast of St Francis 4th October 1402. The boy was renamed Francis, and it became a name used and honoured by the Mac Namara Clan for centuries.