The name suggests it was once distinctive enough in appearance to earn the description, though what exactly whitened it, whether lime-rendered stonework, pale exposed soil, or something else entirely, is now lost to the landscape.

The fort belongs to a category of monument found across Ireland known as a rath or ringfort, a roughly circular enclosure defined by an earthen bank and ditch, typically used as a farmstead during the early medieval period, roughly between the fifth and twelfth centuries. What survives at Lackaboy is a univallate example, meaning it has a single enclosing bank rather than the two or three concentric rings seen at more elaborate sites. That bank is substantial: about seven metres wide at its base and rising to a maximum external height of 2.6 metres. The fosse, the ditch cut around the outside of the bank, is 1.4 metres wide and sits roughly a metre below the level of the surrounding land. The interior measures approximately 30 metres north to south and 32.4 metres east to west, and it sits at a higher elevation than the fields around it, sloping gently southward. Two openings breach the bank: one to the north, four metres wide, and a wider entrance to the southeast measuring six metres. A field bank runs immediately along the eastern side of the fort in a north to south direction, suggesting the agricultural geography of the area has been organised around the monument for some time. The site was documented in the North Kerry Archaeological Survey, published in 1995 by Catherine Toal.