It is easy to overlook such a thing, but what lies here is a togher, a timber trackway laid across boggy ground to allow people or animals to cross terrain that would otherwise have been impassable. This one runs east to west and measures just 1.22 metres wide, constructed from lengths of roundwood laid longitudinally, the individual timbers averaging around six centimetres in diameter.

The materials used were alder and oak, both common choices in Irish wetland construction. Alder in particular has a long association with waterlogged environments; it resists decay unusually well when kept permanently wet, which is precisely why so many ancient toghers have survived at all. The peat that swallowed these trackways acted as a preservative, sealing out the oxygen that would otherwise have broken the wood down over centuries. Among the surviving material at Derrylough, one piece appears to be a peg that retains visible toolmarks, a small but telling detail. It is the kind of trace that places a real person at the site, someone who shaped a piece of wood with a blade and drove it into the ground, fixing the structure in place before moving on.