Kiel is the capital and chief port of Schleswig Holstein. Lübeck, Flensburg, and Neumünster are the major cities. Schleswig-Holstein occupies the southern part of the Jutland peninsula and is bordered by the North Sea on the west, the Baltic on the east, Denmark in the north and the Elbe River in the south. The Kiel Canal links the North Sea and the Baltic. The Eider River forms the historic border between the former duchies of Schleswig in the north and Holstein in the south.
Schleswig and Holstein have at different times belonged in part or completely to either Denmark or Germany, or have been virtually independent of both nations. The exception is that Schleswig had never been part of Germany until the Second War of Schleswig in 1864. For many centuries, the King of Denmark was both a Danish Duke of Schleswig and a German Duke of Holstein, the Duke of Saxony. Essentially, Schleswig was either integrated into Denmark or was a Danish fief, and Holstein was a German fief and once a sovereign state long ago. Both were for several centuries ruled by the kings of Denmark. In 1721 all of Schleswig was united as a single duchy under the king of Denmark, and the great powers of Europe confirmed in an international treaty that all future kings of Denmark should automatically become dukes of Schleswig, and consequently Schleswig would always follow the same line of succession as the one chosen in the Kingdom of Denmark.
More about the history visit the following:
Archives and Records
The GGS collection of Germanic Genealogy Books at Concordia University in St. Paul, MN has 9 books specifically on Schleswig-Holstein genealogy, of those 9 books 1 is in German.