Croghan Hill is the remains of an extinct volcano and rises from the Bog of Allen in County Offaly. Though only 232 m high it commands extensive views of the surrounding midland counties, across the flat, low-lying expanse of the Bog of Allen. The village of Croghan is located on the southern slope of the hill.
The mound at the summit Croghan Hill is thought to be a bronze age burial place. It is believed that a Bishop MacCaille had his church there and lived around the time of St Patrick in the fifth century. The area also has strong associations with St. Bridget, who is said to have been born near Croghan hill.