The island extends northward to within 9.5 miles (15 kilometres) of the northwestern extremity of Unst.

Locations are as gazetted; obviously some islands may extend over large areas.

The islands extend about 275 miles (440 km).

This large island extends into the continental coast, from which it is divided by the channels just mentioned.

The islands extend in a line until they reach the mainland.

The island was small and extended no further than Bartonholm, nowhere near the size of the present day Ardeer peninsula.

A few small islands and rocks, the St Alouarn Islands, extend further to the south.

The islands extends from 6 to 14 North latitudes and from 92 to 94 East longitudes.

The island of Sylt extends for 38 km in a north-south direction and on its northern peak at Königshafen is only 320 m wide.

In summer the island is mainly under the influence of a shallow trough of low pressure extending from the great continental depression centred over Western Asia.