It is a togher, the Irish term for a bog road or trackway, and this particular example is modest in scale but precise in its making: eleven roundwood poles of ash and birch, laid in a compact arrangement just 1.6 metres wide and roughly a quarter of a metre deep.

What makes toghers remarkable as a category of monument is the combination of their ordinariness and their survival. They were functional objects, built to solve an immediate problem, getting people, animals, or goods across wet and unstable ground. Yet the anaerobic, acidic conditions of Irish bogland preserve organic material with extraordinary fidelity, and so what was once a muddy practical solution becomes, centuries or millennia later, a precise record of carpentry. The Derrynagran togher shows evidence of woodworking on its timbers, meaning the poles were not simply thrown down as they came but shaped and prepared before use. The roundwoods themselves range from seven to ten centimetres in diameter, the kind of slender, manageable material that would have been readily coppiced or gathered from wet woodland margins, ash and birch both being common in such environments across the Irish midlands.