The River Glyde rises in the town of Bailieborough in Cavan. Some smaller tributaries of the Glyde are the River Dee and the Killanny Rivers which contain stocks of sea trout and salmon. The Glyde flows in a south-easterly direction before entering the sea at Annagassan in Louth, site of the recently rediscovered ninth-century Viking longphort Linn Duachaill..