Forth

Forth, river and firth (estuary), Scotland. The Forth rises near Aberfoyle at the juncture of the Avondhu River and Duchray Water. It drains an area of about 1670 sq km (about 645 sq mi). It is joined by the Teith River at Stirling and then flows northeast, widening into the Firth of Forth. The total length of the river is 188 km (117 mi). The firth extends about 77 km (about 48 mi) to the North Sea and is about 28 km (about 17.5 mi) wide at its mouth. At Queensferry the river is spanned by the Forth Bridge, a cantilever railway bridge built in 1890. Nearby is the Forth Road Bridge, a suspension bridge built in 1964. The Forth is navigable to Alloa by vessels of up to about 300 gross tons; it is navigable as far inland as Stirling by vessels of up to about 100 tons. The firth is connected to the Firth of Clyde by the Forth and Clyde Canal. Bo'ness, Burntisland, Grangemouth, Kirkcaldy, and Leith are the principal ports on the Firth of Forth. Important salmon and herring fisheries and resorts are located along the lower course of the Forth River.