The Firth of Forth is the estuary

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 or firth

Firth

Firth is the word in the Lowland Scots language and in English used to denote various coastal waters in Scotland and England. In mainland Scotland it is used to describe a large sea bay, or even a strait. In the Northern Isles it more usually refers to a smaller inlet...

 of Scotland's

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 River Forth

River Forth

The River Forth , long, is the major river draining the eastern part of the central belt of Scotland.The Forth rises in Loch Ard in the Trossachs, a mountainous area some west of Stirling...

, where it flows into the North Sea

North Sea

In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

, between Fife

Fife

Fife is a council area and former county of Scotland. It is situated between the Firth of Tay and the Firth of Forth, with inland boundaries to Perth and Kinross and Clackmannanshire...

 to the north, and West Lothian

West Lothian

West Lothian is one of the 32 unitary council areas in Scotland, and a Lieutenancy area. It borders the City of Edinburgh, Falkirk, North Lanarkshire, the Scottish Borders and South Lanarkshire....

, the City of Edinburgh and East Lothian

East Lothian

East Lothian is one of the 32 council areas of Scotland, and a lieutenancy Area. It borders the City of Edinburgh, Scottish Borders and Midlothian. Its administrative centre is Haddington, although its largest town is Musselburgh....

 to the south. It was known as Bodotria in Roman times.
Geologically, the Firth of Forth is a fjord

Fjord

Geologically, a fjord is a long, narrow inlet with steep sides or cliffs, created in a valley carved by glacial activity.-Formation:A fjord is formed when a glacier cuts a U-shaped valley by abrasion of the surrounding bedrock. Glacial melting is accompanied by rebound of Earth's crust as the ice...

, formed by the Forth Glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

 in the last glacial period.

The river is tidal as far inland as Stirling

Stirling

Stirling is a city and former ancient burgh in Scotland, and is at the heart of the wider Stirling council area. The city is clustered around a large fortress and medieval old-town beside the River Forth...

, but generally it is considered that the inland extent of the firth ends at the Kincardine Bridge

Kincardine Bridge

The Kincardine Bridge is a road bridge crossing the Firth of Forth from Falkirk council area to Kincardine-on-Forth, Fife, Scotland.-History:The bridge was constructed between 1932 and 1936, designed by Donald Watson...

.

There are a number of towns which line the shores, as well as the petrochemical

Petrochemical

Petrochemicals are chemical products derived from petroleum. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as corn or sugar cane....

 complexes at Grangemouth

Grangemouth

Grangemouth is a town and former burgh in the council area of Falkirk, Scotland. The town lies in the Forth Valley, on the banks of the Firth of Forth, east of Falkirk, west of Bo'ness and south-east of Stirling. Grangemouth had a resident population of 17,906 according to the 2001...

, the commercial dock

Dock (maritime)

A dock is a human-made structure or group of structures involved in the handling of boats or ships, usually on or close to a shore.However, the exact meaning varies among different variants of the English language...

s at Leith

Leith

-South Leith v. North Leith:Up until the late 16th century Leith , comprised two separate towns on either side of the river....

, oilrig

Oil platform

An oil platform, also referred to as an offshore platform or, somewhat incorrectly, oil rig, is a lаrge structure with facilities to drill wells, to extract and process oil and natural gas, and to temporarily store product until it can be brought to shore for refining and marketing...

 former construction yards at Methil

Methil

Methil is an eastern coastal town in Scotland. It was part of the former Burgh of Buckhaven and Methil. It lies within a continuous urban area described as Levenmouth.Methil lies geographically between Largo bay to the east and Wemyss Bay to the west....

, the ship-breaking facility at Inverkeithing

Inverkeithing

Inverkeithing is a town and a royal burgh in Fife, Scotland, located on the Firth of Forth. According to population estimates , the town has a population of 5,265. The port town was given burgh status by King David I of Scotland in the 12th century and is situated about 9 miles north from...

 and the naval dockyard at Rosyth

Rosyth

Rosyth is a town located on the Firth of Forth, three miles south of the centre of Dunfermline. According to an estimate taken in 2008, the town has a population of 12,790....

, with numerous other industrial areas including the Forth Bridgehead area, Burntisland

Burntisland

Burntisland is a town and former royal burgh in Fife, Scotland on the Firth of Forth. According to an estimate taken in 2008, the town has a population of 5,940....

, Kirkcaldy

Kirkcaldy

Kirkcaldy is a town and former royal burgh in Fife, on the east coast of Scotland. The town lies on a shallow bay on the northern shore of the Firth of Forth; SSE of Glenrothes, ENE of Dunfermline, WSW of Dundee and NNE of Edinburgh...

, Bo'ness

Bo'ness

Bo'ness, properly Borrowstounness, is a coastal town in the Central Lowlands of Scotland. It lies on a hillside on the south bank of the Firth of Forth within the Falkirk council area, north-west of Edinburgh and east of Falkirk. At the 2001 census, Bo'ness had a resident population of 13,961...

 and Leven

Leven, Fife

Leven is a seaside town in Fife, set in the east Central Lowlands of Scotland. It lies on the coast of the Firth of Forth at the mouth of the River Leven, north-east of Kirkcaldy and east of Glenrothes....

.

The Kincardine Bridge and the famous Forth Road Bridge

Forth Road Bridge

The Forth Road Bridge is a suspension bridge in east central Scotland. The bridge, opened in 1964, spans the Firth of Forth, connecting the capital city Edinburgh, at South Queensferry, to Fife, at North Queensferry...

 and Forth Bridge

Forth Bridge (railway)

The Forth Bridge is a cantilever railway bridge over the Firth of Forth in the east of Scotland, to the east of the Forth Road Bridge, and 14 kilometres west of central Edinburgh. It was opened on 4 March 1890, and spans a total length of...

 carry traffic across the Firth.