River Lagan
 The River Lagan (from Irish Abhainn an Lagáin meaning river of the low-lying district; Ulster Scots: Lagan Wattèr) is a major river in Northern Ireland which runs 40 miles (60 km) from the Slieve Croob mountain in County Down to Belfast where it enters Belfast Lough an inlet of the Irish Sea. The River Lagan forms much of the border between County Antrim and County Down in the east of Ulster. It rises as a tiny fast moving stream off the Transmitter road near to the summit of Slieve Croob.