It is situated near the head of Wigtown Bay, 18 m.
On the south this kingdom bordered on the territories of the Niduari Picts of Galloway, including the modern counties of Wigtown and Kirkcudbright, a region which from the middle of the 7th century seems to have been in the possession of the Northumbrians.
The Scottish shore, however, is not continuously flat, and such elevations as Criffell (1866 ft.), Bengairn (1250) and Cairnharrow (1497), above Wigtown Bay, rise close to it.
Thus in Scotland the Cree and other streams enter Wigtown Bay; the Dee, Kirkcudbright Bay; Auchencairn Bay and Rough Firth receive numerous small streams, and the Nith discharges through a long estuary.
The fisheries are extensive, and though there are no ports of the first magnitude on the firth, a considerable shipping trade is carried on at Whitehaven, Harrington, Workington, Maryport and Silloth in Cumberland, and at Annan, Kirkcudbright, Creetown and Wigtown on the Scottish side.