The Glendun River flows through the Northern Glens of Antrim in Northern Ireland, emptying into Cushendun Bay on the northeastern coast. It is a recognized primary salmon river within the DAERA (Department of Agriculture, Environment and Rural Affairs) management area and serves as one of the key index rivers for Atlantic salmon and sea trout monitoring in Northern Ireland. The river has been the subject of ongoing habitat surveys, fish counter installations, and conservation limit assessments, reflecting its ecological importance to the region's inland fisheries. The Glendun is notable for its late summer and autumn salmon run, which forms the backbone of its salmon population, and it also supports a long-monitored sea trout population that has shown overall increasing trends in juvenile recruitment over more than two decades of survey data.