The River Dee () is a river in eastern Ireland, flowing from County Cavan to flow into the River Glyde near the coast, in County Louth.
In the Táin Bó Cúailnge, Cúchulainn fights Ferdia at Ath Carpat ("chariot ford") on the river NÃÂth. The river takes its name from the Irish nÃÂth, meaning "combat". The modern name Dee derives from the town of Ardee (Baile ÃÂtha Fhirdhia, "town of Ferdiad's ford").
The River Dee rises from a spring near Bailieboro in County Cavan and flows in an easterly direction for through County Meath and County Louth before joining with the River Glyde at the village of Annagassan. The Dee in turn has three main tributaries: the Killary River which joins south of Drumconrath (Drumcondra), County Meath, the Gara River which joins west of Ardee, County Louth, and the White River which flows north from Dunleer, County Louth. There is one lake on the Dee, Whitewood Lake, near Nobber, County Meath.
The River Dee is a brown trout fishery.