The Forth River
Forth River, a major river of Scotland. The Forth River begins near Loch Lomond and flows southeastward for some 65 miles (105 km). It then widens into the Firth of Forth, a broad estuary in the North Sea. The firth is nearly 50 miles (80 km) long and has a maximum width of almost 20 miles (32 km). Edinburgh, Leith, and Kirkcaldy are the principal cities on its shores. Several bridges span the firth just west of Edinburgh.