Ive yet to be able to find this well. It is in on an old estate and everytime I try to get in to see it there are bullocks or something blocking my way. The best to park to try is at a Bus Eireann stop adjacent to the gates of the demense. The road in is basically one way with few places to turn so you would have to reverse back out. The big country house is meant to have been built on a passage mound.
Taken from Sacred Ireland – Cary Meehan
"The Boyne is closely linked with the goddess Boand or Bó Fhinn, the White Cow Goddess who is part of the earliest Irish mythology. She is said to inhabit a sí or mound here where Newberry house now stands, at the source of the river Boyne. The well is described as having nine hazel trees overhanging it. When the nuts fell into the well, their magical properties went into the water. It was said that anyone drinking its water in June would become a poet. Boand was, among other things, the goddess of poetry.
Carbury used to be known as 'Sidh Neachtain' which means 'the Fairy Mound of Neachtain'. Neachtain is mentioned in the Annals of the Four Masters as a Tuatha Dé Danann leader and king of Ireland for one year in 45AD. He is variously known as Neachtain or Nuadha and also as the magical figure Neachtain, the water god, whose task was to care for the well and make sure its power was not unleashed in a destructive way. There are a number of versions of the following story.
Neachtain and Boand were married but she was never allowed to visit the sacred well with her husband. He and his brothers were the keepers of the well and even its location was kept a secret. They made regular visits there and on one occasion, overcome by curiosity, Boand followed them. Later she went back herl
self and tasted the forbidden water which then rose up and overwhelmed her, flowing out to sea and forming the sacred waters of the river Boyne, a watery embodiment of her spirit as the goddess Boand."