The western landscape mostly consists of rugged cliffs, hills and mountains. The central lowlands are extensively covered with glacial deposits of clay and sand, as well as significant areas of bogland and several lakes. The highest point is Carrauntoohil (), located in the MacGillycuddy's Reeks mountain range in the southwest. River Shannon, which traverses the central lowlands, is the longest river in Ireland at in length. The west coast is more rugged than the east, with numerous islands, peninsulas, headlands and bays.