From 1933 onwards, after the Nazi seizure of power, the Gaue increasingly replaced the states as administrative subdivisions in Germany.

With the return of the Saar Basin to Germany on 1 March 1935, the two regions were merged and formed the new Gau Pfalz-Saar.

After the outbreak of the Second World War and the defeat of France in 1940, the French département of Moselle, renamed "CdZ-Gebiet Lothringen", was added to the Gau on 30 November 1940.

Gauleiter Bürckel hoped that Westmark would be extended as far as Germany's future western border, especially keeping in mind the ore region of Briey-Longwy in the département of Meurthe-et-Moselle.

Local Gauleiters were in charge of propaganda and surveillance and, from September 1944 onwards, the Volkssturm and the defence of the Gau.