The low walls, built from stone or a mixture of earth and stone, are still there beneath the vegetation, enclosing a landscape that once fed people but has long since been reclaimed by rough pasture and the bog pressing in from either side.

What makes this place quietly affecting is the trace of lazy beds visible in the clearings, places where the scrub has thinned enough to reveal the old ridged cultivation pattern beneath. Lazy beds, despite the name, were a labour-intensive technique in which soil was mounded into long parallel ridges to improve drainage and maximise the growing surface, particularly for potatoes. They are found across Ireland wherever marginal land was pressed into use, and in many cases they date to periods of intense population pressure before the Famine. The field system at Derrylahan is thought to be eighteenth or nineteenth century in origin, which places it squarely within that era of difficult, often desperate, agricultural expansion onto land that wealthier farmers in better conditions would not have bothered with. Immediately to the north lies a separate enclosure, suggesting this was once a more organised and inhabited landscape than its current wildness implies.