This is a togher, an ancient Irish term for a raised trackway constructed across waterlogged or boggy ground, and the example at Coolnahinch is a quiet piece of engineering that has outlasted almost everything built above ground in the same era.

The structure runs on an east-northeast to west-southwest alignment, measuring two metres wide and roughly twenty centimetres deep. It was built using a combination of longitudinal and transverse roundwood timbers along with brushwood, the whole thing woven together from ash, birch, and oak. That mixture of species is worth pausing over. Each wood brings different properties: oak for durability, ash for flexibility and strength, birch for its abundance in wetland margins. Toghers like this one were practical solutions to a very Irish problem, allowing people, animals, and goods to move across terrain that would otherwise have been impassable. They appear at various points throughout Irish prehistory and the early medieval period, and the bogs that once made them necessary have, ironically, also preserved them, slowing the decay that would have consumed them in drier ground centuries ago. The Coolnahinch togher was recorded through the work of the Irish Archaeological Wetland Unit at University College Dublin, a research programme that systematically documented bog roads and related wetland monuments across the Irish midlands.