Of the many church ruins in Athy, St. Michaels is perhaps the most ancient. It was built in the fourteenth century. Some of the vestry and sidewalls have disappeared, but there is still some of the original church remaining.
The dedication to St. Michael is derived from the St. Michael family who were lords of Athy and it is quite probable that it was this family who were the founders of the church. A small and very ancient cross lies within the church grounds and it is said that a cross or font is buried in a grave, within the ruins. There was at one time an arch that stood in front of St. Michaels, but during some renovations many years ago, this was taken down.