The Dee and most of its tributaries arise in Wales. Though a section of it passes through England, it passes into Wales once again before discharging into the Irish Sea via the Dee estuary. For other rivers entering the Irish Sea and Cardigan Bay from Wales, see List of rivers of Wales. Only those tributaries of the River Dee which flow wholly or partly in England are listed here - for a complete list of the rivers and watercourses of the Dee catchment see List of rivers of Wales.