River Nith

River Nith
The estuary of the River Nith, opening into Solway Firth south of Dumfries
Country	Scotland
Basin features
Main source	Enoch Hill 55°19′41″N 4°17′02″W / 55.328°N 4.284°W / 55.328; -4.284
River mouth	Solway Firth
Basin size	1,230 km2 (470 sq mi)
Physical characteristics
Length	71 mi (114 km)

The River Nith (Scottish Gaelic: Abhainn Nid; Latin: Novius) is a river in South West Scotland.

The Nith rises in the Carsphairn hills of East Ayrshire, more precisely between Prickeny Hill and Enoch Hill, 7 km east of Dalmellington. For the majority of its course it flows in a generally southern direction through Dumfries and Galloway, before spilling into the Solway Firth at Ards point.

The territory through which the river flows is called Nithsdale (historically known as "Stranit" from Scottish Gaelic: Strath Nid, "valley of the Nith").

For estuaries the principle followed is that the river should be visible at all times. The measurement therefore follows the centre of the river at low tide and the mouth of the river is assumed to be at the coastal high tide mark. In Scotland this does not generally make a significant difference, except for rivers draining into shallow sloping sands of the Irish Sea and Solway Firth, notably the Nith. At low tide, the sea recedes to such an extent that the length of the Nith is extended by 13 km to 113.8 km (70.7 miles), making it Scotland's seventh longest river.

The estuary of the River Nith is an important site for wildfowl, and is protected at an international level as part of the Upper Solway Flats and Marshes Ramsar site and Special Protection Area, and as part of the Solway Firth Special Area of Conservation. At a national level, the area is a Site of Special Scientific Interest and is within the Caerlaverock National Nature Reserve.

The Nith Estuary National Scenic Area recognises the scenic value of the area.