Following the First Partition in 1772 the Kingdom of Prussia established the West Prussian province and the Netze District on annexed Pomerelian and Greater Polish (and Kuyavian) territories respectively.

Their population was predominantly Catholic and Polish-speaking, while a sizable Protestant German minority settled mainly in the western parts.

Ethnic tensions were exacerbated by the Germanisation policies of the Berlin government and the anti-Catholic Kulturkampf measures enacted by Chancellor Otto von Bismarck.

Upon the German defeat in World War I, another Greater Poland Uprising broke out in 1918, which aimed to incorporate the lands once annexed by Prussia into a re-established Polish state.

The forces of the Polish Military Organisation were able to oust the German administration from the bulk of the Greater Polish lands, whereafter the Posen governor (Landeshauptmann) Ernst von Heyking was forced to retire to Meseritz (Międzyrzecz) and de facto only ruled over the far western, predominantly German settled districts at the border with the adjacent Prussian provinces of Pomerania, Brandenburg and Silesia.

With the entry into force of the German Ostmark law on 1 July 1922, the province was created out of those smaller western parts of former Posen and West Prussia that remained with the Weimar Republic.

Kube, notorious for his corruption, ruled over both provinces until he was deposed after entering into a conflict with the Nazi jurist Walter Buch, father-in-law of mighty Martin Bormann.

The share of the vote of the Polish-Catholic People's Party was stable at around 3% in all state and Reichstag elections in the Weimar Republic.

According to the census of 1925, the districts of Bomst (20.6%), Flatow (16.8%) and Meseritz (5.8%) had the highest proportions of Polish speakers (including bilinguals).