It is a togher, the Irish term for a wooden trackway laid across wet or marshy ground, and the example recorded at Derryglogher is a quietly precise piece of ancient engineering: two metres wide, roughly ten centimetres deep, and aligned on a north-north-east to south-south-west axis, as though someone once had a clear sense of where they needed to go.

The construction is straightforward but deliberate. Ten roundwoods, cut from birch and alder, were laid longitudinally in a compact layer to form the road surface. Both timbers were well chosen for the purpose: birch and alder are among the woods most resistant to decay in waterlogged conditions, which is precisely why so many toghers built centuries or even millennia ago have survived at all. The peat acts as a preserving medium, cutting off the oxygen that would otherwise rot the wood. Toghers range considerably in their complexity, from single planks thrown across a drain to substantial multi-layered platforms, and this class 3 example sits in the middle range, functional and unadorned. Research into sites like this was carried out by the Irish Archaeological Wetland Unit at University College Dublin, which documented bogland archaeology across the Irish midlands before much of it was lost to turf cutting and drainage.