A fjord is normally a glacially overdeepened valley, usually narrow and steep-sided, extending below sea level and filled with salt water. A fjord is formed when a glacier retreats after carving its typical U-shaped valley and the sea fills the resulting valley floor. This forms a narrow, steeply sided inlet (sometimes as deep as 1401m) connected to the sea. This shallow threshold and the protection afforded by the valley's sides generally means that fjords are excellent natural harbours. Consequently fjords often provide a home-port to fishing fleets, and, in industrialised locations have come to be used for fish farming and shipbuilding.
Other articles of interest; Development geography, Weathering, Demographic transition, Tectonic plate.