This is a togher, an ancient form of trackway built directly into a bog by laying brushwood flat across the soft surface, creating a firm path through terrain that was otherwise impassable. The Derrylough example is a class 3 togher, a designation reflecting its relatively modest construction, and it measures 1.6 metres wide and roughly 0.3 metres deep, running on an east-west orientation through the wetland.

What makes the engineering here quietly remarkable is the precision of its simplicity. The brushwood used consists of hazel and birch stems, ranging from about 15 to 45 millimetres in diameter, laid both transversely and longitudinally to create a stable, interlocking surface. There is also possible evidence of coppicing, the practice of cutting trees or shrubs back to the base to encourage the growth of multiple straight shoots, which would suggest that whoever built this trackway was not merely gathering whatever timber came to hand, but actively managing their woodland to produce suitable material. That kind of organised land use points to a community thinking ahead, maintaining resources across seasons or years. Toghers of this type are known from across the Irish midlands, where bog formation over thousands of years has preserved organic materials that would have rotted away entirely in drier ground, making such features rare windows into everyday movement and labour in early Ireland.