Lough Oughter is a sprawling, labyrinthine lough west of Cavan town, broken into dozens of smaller water bodies by the drumlin hills that rise from its shallow shores. The result is one of Ireland's most distinctive lake landscapes — less a single body of water than a watery maze of channels, reed beds, and wooded islets. It is excellent habitat for birds, and a nationally important breeding site for several waterfowl species.
A 13th-century tower house, Cloughoughter Castle, rises from a small island near Killykeen Forest Park and is visible from the shore. Killykeen itself offers well-marked walking and cycling trails through lakeside oak and birch woodland, with views over the lough at every turn. Canoe hire is available nearby, and paddling through the reedy channels is one of the best ways to experience the area.