That collision of eras, an early medieval island dwelling later conscripted into nineteenth-century land drainage, gives this small site in County Westmeath an oddly layered character.

A crannog is an artificial or partially artificial island, typically constructed during the early medieval period as a defensive or high-status dwelling, and the one at Culleen Beg sits in the marshy ground at the north-western corner of McEvoy's Lough, a small lake connected to the larger Lough Drin and Slevin's Lough to the east and south. The mound measures roughly fourteen metres east to west and thirteen metres north to south, rising less than a metre above the surrounding boggy ground. When Victor Buckley recorded it in 1982, the site had already drifted noticeably from its original waterline; it now sits about ten metres from the present lake edge, though it would originally have been only eighteen metres from the shore as it stood before the surrounding land was altered. Two oak timbers from what appears to have been a palisade, a defensive wooden fence or stockade, remain visible on the southern edge, one standing forty centimetres above the ground and thirty centimetres in diameter, the other slighter and barely protruding. A faint trace of a causeway leads northward toward dry land, though this feature may itself be a nineteenth-century addition rather than an original approach. The disturbance caused by tree roots in the western interior compounds a picture of a site that has been quietly reshaped by every passing century.