Beneath the modern road network around Lismore in County Waterford, an older route persists, quietly legible in field banks, farm avenues, and minor roads that seem to lead nowhere in particular until you realise they are following something much older. This is a stretch of the Rian Bó Phádraig, traditionally translated as the track or way of Patrick's cow, the ancient highway of the Decies, the historical territory that covered much of what is now County Waterford.

The route was traced and written up in 1905 by the Reverend P. Power, whose paper in the Journal of the Royal Society of Antiquaries of Ireland remains the principal source for understanding its course. Power identified a section beginning roughly two kilometres west of Lismore, where the road to Glencairn runs, and followed it down the avenue to the farm of Lismore Castle, then eastward along a field bank in the direction of the castle itself. On the eastern side of Lismore the road continues as a minor road passing through Ballyea and Drumroe, eventually arriving at the ford of Affane on the Blackwater. The total length of this traceable section runs to approximately eight kilometres. Affane itself was a significant crossing point on the Blackwater, and the ford there would have made it a natural waypoint on any long-distance route through the region. Ancient roads of this kind were not engineered in the Roman sense but were habitual lines of movement, worn into the landscape over generations and often preserved by the boundaries and patterns of later land use that inadvertently followed their course.