It is a togher, an ancient trackway built from timber laid across wet or waterlogged ground to allow safe passage on foot, and this particular example is a quietly precise piece of early engineering. The logs are ash roundwood, each averaging around six and a half centimetres in diameter, laid regularly side by side to form a surface roughly two and a half metres wide and only about ten centimetres deep. Several of the pieces still carry toolmarks, faint but legible evidence of the hands that shaped and placed them.

Toghers are among the more intimate survivals in the Irish archaeological record. Where a ringfort or a souterrain announces itself through earthwork or stone, a togher simply lies flat and waits, preserved by the oxygen-starved conditions of the bog that swallowed it. The choice of ash is worth noting; the timber is tough and flexible, qualities that would have mattered on unstable ground. The regularity of the laying suggests this was not an improvised crossing but a considered piece of construction, a road in the practical sense even if its scale seems modest by later standards. The Derrindiff togher was identified and recorded as part of the work of the Irish Archaeological Wetland Unit, based at University College Dublin, which systematically surveyed the midland bogs for exactly this kind of submerged infrastructure before drainage and turf-cutting could erase it entirely.