The location was originally sought out as a peaceful retreat by St. Kevin because of its remoteness and serenity, but several disciples who wished to follow his teachings built a temporary hamlet of churches, chapels and living quarters in the valley below the site of his hovel. This soon grew and eventually, at the height of its popularity, was one of the main religious universities in Ireland.
The name Glendalough comes from the Irish Gleann Dá Locha meaning the glen (valley) of two lakes. The monastery site is located between two lakes (Lower Lake and Upper Lake) and one of the most popular tourist sites in Wicklow.
The monastic site includes a 33 metres tall Round Tower and St. Kevin's Cross, a Celtic High cross. The round tower was built during the era of the viking invasions in Ireland (up to and around AD1066), in order to protect the religious relics, books and chalices used around the monastery at the time.