This article is about the region of Schleswig on the German/Danish border. There is also Schleswig, Iowa in the United States of America.

The region of Schleswig (Slesvig in Danish) covers the area about 30 km north and 40 km south of the border between Germany and Denmark. Traditionally, the area's significance lies in the transfer of goods between the North Sea and the Baltic Sea, connecting the trade route through Russia with the trade routes along Rhein and the Atlantic coast.

Schleswig was together with Holstein the cause for several disputes between Germany and Denmark in the 19th century. The Duchy of Schleswig was a fief under the Danish Crown until 1864, from 1460 in personal union with Denmark. From 1864 Schleswig-Holstein was part of Prussia until a referendum in 1920 resulted in Northern Schleswig joining Denmark, whereas Southern Schleswig voted to remain a part of Germany.

See also: City of Schleswig, History of Schleswig-Holstein