It is a togher, a type of ancient trackway built to carry people and animals across waterlogged or marshy ground, and its survival is owed entirely to the anaerobic, oxygen-free conditions of the peat that has covered it for centuries.

The Derrynagran togher is a class 3 example, meaning it was constructed using a layered timber technique of some sophistication. The road runs on a northeast to southwest orientation and measures 2.2 metres wide and roughly 12 centimetres deep. Its upper surface, the part that would have been walked upon, consists of hazel brushwood laid longitudinally, with individual pieces averaging around 2.5 centimetres in diameter. Beneath that sits a substructure of stouter ash roundwood, averaging 6 centimetres in diameter, which gave the whole thing its load-bearing strength. Crucially, some of the timbers show evidence of woodworking, meaning the people who built this were not simply throwing branches into a bog but shaping and preparing their materials deliberately. Hazel and ash are both native Irish species well suited to this kind of construction: hazel is flexible and lightweight, while ash is notably strong and resistant to splitting, making it a practical choice for the foundational layer.