The site was first used in Neolithic times, dating back to around 2000BC. There are a number of burial mounds within and around the site of a fort. The fort is circular with four embankments and ditches, which was further secured by its location in an area of bog land. The remains of 'Old Croghan Man', a well preserved Iron Age bog body who is believed to have died (possibly as a sacrifice) between 362 and 175 BC, was found in a bog close by. The remains are in the National Museum of Ireland in Dublin.
Continue along the M4 west from Maynooth. Then at Junction 9 go southwest along the R402 to Edenbury and west on the R441 to Rhode. Continue of the minor road west to Croghan and the site is located at Croghan Hill, about ten miles northeast of Tullamore in County Offaly.