This is a togher, a type of timber trackway laid across waterlogged or marshy ground to allow people and livestock to pass where the land would otherwise be impassable. The Irish boglands have preserved dozens of these structures across the centuries, holding them in conditions that would rot wood to nothing almost anywhere else.

The Derrynagran togher runs approximately 105 metres on a north-south orientation, with a width of around three metres, suggesting it was wide enough for practical use rather than simply a footpath. It was constructed from transverse roundwood, meaning the timbers were laid across the direction of travel, each piece averaging about seven centimetres in diameter and spaced roughly twenty centimetres apart. A single birch peg was found exposed in the face of a nearby drain, positioned at one edge of the trackway, likely serving to pin the structure in place and prevent lateral movement as people passed over it. Toolmarks were visible on the timbers, which tells us this was not a matter of simply throwing branches across wet ground; the wood had been worked and shaped before being laid down. The presence of both birch and ash suggests the builders were selecting specific species, possibly for their flexibility, their availability locally, or their resistance to decay.