The North Sea lies between the island of Great Britain and the coasts of Belgium, the Netherlands, Germany, and Denmark. It extends north to the Norwegian Sea in the lattitudes of the Shetland Islands. Its maximum dimension are about 400 miles in width and 700 miles in length.
The bed of the North Sea is a recently submerged portion of the Continental Shelf of Europe. At the close of the last Ice Age, the land was high and the resulting plain was a land passage between what is now continental Europe and the British Isles.