Yet what was uncovered at Derrindiff is a togher, a type of bog road built from timber and brushwood to allow people and animals to cross otherwise impassable wetland, and the construction detail preserved here is quietly remarkable. The worked ends of the roundwood timbers show both chisel and wedge-point cuts, meaning that Iron Age craftspeople were shaping this material deliberately, not simply throwing branches into the mud.

Excavation in 2002 produced a radiocarbon date placing the trackway somewhere between 357 and 234 BC, firmly in the Irish Iron Age. The main exposed section measured eighteen metres in length, with parallel roundwood poles forming the running surface and pieces of brushwood laid transversely beneath, essentially a mattress of woven or stacked wood to distribute weight across the bog. Vertical pegs and diagonal brushwood pieces helped stabilise the structure, and a second spread of similar material was identified around eighteen metres to the north-east, most likely a continuation of the same road. The section in between had probably been removed by peat-milling before anyone thought to look. The two fragments together suggest a coherent, purposefully engineered route, not an improvised crossing.