The River Lagan, which inks the district with the neighbouring council areas of Lisburn and Craigavon, rises as a tiny fast moving stream off the Transmitter road near to the summit of Slieve Croob Mountain. From here it continues on its journey to Belfast through Dromara and Dromore.
On the lower slopes of the mountain it is joined by another branch from Legananny (Cratlieve) Mountain – just opposite Slieve Croob. At Dromara, about four miles from its source, its height above the sea is 390 feet- approximately 119 metres.
As the river continues on its journey to Belfast it turns east to Magheralin into a broad plain between the Antrim plateau and the Ordovivian plateau of Down. It was this plain, in the Irish Lagán, which is said to have given the river its name, the abhainn án Lagáin or the Lagan Water, as it was literally translated in the seventeenth century.
Myth has it that Saint Patrick slayed a River Demon that was polluting and reeking havoc along the Lagan. Today the Lagan Lookout at Donegal Quay, Belfast details the recent work on Laganside to refresh and restore the river.
There are canoe steps in Dromore Park and the local schools use the River Lagan near Dromore for canoeing.