The Czech population had to accept German citizenship or were expelled and forcibly relocated to the Czechoslovak rump state, which itself from 15 March 1939 was occupied by Germany and incorporated as the "Protectorate of Bohemia and Moravia".

After the proclamation of the Protectorate of Bohemia and Moravia, the Reichsgau was formally established by law on 25 March 1939, in effect from 15 April, borders were adjusted and the administrative structure was fixed on May 1.

Smaller areas in the east, such as the Hlučín Region, were ceded to the Prussian Province of Silesia, while the western and southern Sudetenland territories were attached to the Bavarian Gau Bayreuth as well as to the Austrian Reichsgaue Oberdonau and Niederdonau.

After Germany's defeat in World War II, Czechoslovakia was re-established as an independent state and the Sudeten German population was expelled.

It was designed to concentrate the Jewish population from the Protectorate and gradually move them to extermination camps and also held Western European and German Jews.