 The River Nore flows southward past the plateau's western flank, the River Barrow past its eastern flank and it is dissected by the River Dinin, which flows through Castlecomer itself.The landscape consists of the a large area of upland lying between the river valleys of the Barrow and Nore.The eastern section, which is the larger and more elevated part of the plateau is known as the "Rossmore Plateau", after the village of Rossmore, County Laois, which is situated at the northeastern extremity near the highest point on the plateau (334 m) and is just from the town of Carlow below, in the valley of the River Barrow.