Germany > Grenzmark Posen-Westpreussen
The Prussian province Grenzmark-Posen-Westpreussen existed from 1920 until 1938. It consisted of the sections of the former Prussian province of Posen that had not been turned over to Poland after World War I as a result of the Treaty of Versailles. This province was disolved effective 1 Oct 1938, and the area was divided between it neighboring provinces Brandenburg, Schlesien, and Pommern.
Grenzmark-Posen-Westpreussen was situated in the Eastern half of the German Empire and shared borders with Pommern [North], Brandenburg (Neumark) [West], Schlesien [Sounthwest], and Poland [East]. It was divided into six counties [Kreise]: 1.Bomst [1938 divided between Brandenburg and Schlesien]
2.Fraustadt [1938 to Schlesien]
3.Meseritz [1938 to Brandenburg]
4.Netzekreis, created from remnants of the former Posen counties Czarnikau, Filehne and Kolmar in Posen [1938 to Pommern]
5. Schneidemuehl [1938 to Pommern]
6. Schwerin (Warthe) [1938 to Brandenburg]
A map of this area is found here.
After October 1938 a new region [Regierungsbezirk] was created when the remnants of Grenzmark-Posen-Westpreussen situated within the province of Pommern were combined with the counties of Dramburg and Neustettin in Pommern and Arnswalde and Friedeberg/Neumark in Brandenburg. This region was called Regierungsbezirk Grenzmark-Posen-Schneidemuehl, with the administrative capital in Schneidemuehl.
Since the end of World war II this area has belonged to Poland. These borders were formally recognized by the German government after the Reunification of 1990.