This archaeological monument is found on the lawns beside the Upper Lake in Glendalough. It is a stone walled circular enclosure, measuring 20 meters in diameter. It's original purpose and time of construction is a mystery. Similar structures can be found around the country but they were built on a much larger scale for use as defensive forts. The Caher in Glendalough is likely to be have been used as a station (stopping point for prayers) for those on pilgrimage across the mountains to the remains of St. Kevin's monastery.