County Down, (An Dśn in Irish) is one of the six counties of Northern Ireland, covering an area of 2,447 square kilometres. Its population is about 329,000.
Down is the home of the granite Mourne mountains, which sweep down to the sea. They are the well known for their beauty and are the topic of the Irish song "The Mountains of Mourne", by Percy French. The highest peak in the Mournes is Slieve Donard at 2,796 feet (848 metres).
The Newry and Lagan rivers flow through county Down.
Web site: http://www.countydown.com/down.htm