Forth

River in central Scotland, with its headstreams, Duchray Water and Avondhu, rising on the northeast slopes of Ben Lomond. It flows east approximately 105 km/65 mi to Kincardine where the Firth of Forth begins. The Firth is approximately 80 km/50 mi long, and is 26 km/16 mi wide where it joins the North Sea.

The Forth is the seventh longest river in Scotland. At South Queensferry near Edinburgh are the Forth rail (1890) and road (1964) bridges. The Forth and Clyde Canal crosses the lowlands of Scotland and links the east coast and the Firth of Forth to the west coast and the River Clyde, from Grangemouth to Bowling. It was built between 1768 and 1790 and stretches for some 61 km/38 mi. A new coalfield was located beneath the Firth of Forth in 1976. There are salmon and white fisheries in the Forth's basin.