Lough Oughter is a large lake located in County Cavan, Ireland. It is part of the River Erne system and is known for its scenic beauty and rich biodiversity. The lake is surrounded by a variety of habitats, including wetlands and woodlands, making it a popular spot for birdwatching and fishing. The lake features several islands, with Devenish Island being one of the most notable. Lough Oughter is also historically significant, as it contains remnants of ancient structures, including castle ruins and monastic sites. The area is a designated Special Area of Conservation, highlighting its ecological importance.