When Germany overthrew its monarchs in 1918, republics, free-states and people's states were proclaimed in the various former kingdoms, duchies and principalities, each one with slightly different titles and forms of government and wildly different sizes, from the 38 million souls inhabiting the Free State of Prussia to the 50,000 or so each in the Free States of Waldeck and Schaumburg-Lippe. With the monarchs gone, the reason for these disparities was no longer there, and many felt the territory of the Reich should be reorganised to better cope with the new republican reality.
One man who thought so was Hugo Preuß, the left-liberal politician who was tasked by the National Assembly with drafting the new republican constitution. The original draft submitted by Preuß suggested reorganising the states into fourteen new units, pictured below.
- The Free City of Berlin (
Freie Stadt Berlin), covering Berlin in its 1920 (Greater Berlin Act) boundaries. Capital: Berlin (obviously)
- The Free State of Brandenburg (
Freistaat Brandenburg), covering the Prussian provinces of Mark Brandenburg and Pomerania, the Landkreise Jerichow-II, Gardelegen, Osterburg, Salzwedel and Stendal from the Province of Saxony as well as the states of Mecklenburg-Schwerin and Mecklenburg-Strelitz. Capital: also Berlin
- The Free State of Prussia (
Freistaat Preußen), reduced to the parts of the provinces of East and West Prussia still in German hands - this gave it a big exclave in the west, but the peace settlement wasn't finished when the proposal was made, and it's not unlikely that Preuß imagined the Polish Corridor would either stay German or return to Germany. Capital: Königsberg
- The Free State of Silesia (
Freistaat Schlesien), covering the Prussian province of Silesia (excluding the Landkreis Hoyerswerda) plus contiguous parts of the Province of Posen and the
Ämter of Löbau and Zittau from Saxony. Capital: Breslau
- The Free State of Lower Saxony (
Freistaat Niedersachsen), covering the Prussian provinces of Hannover and Schleswig-Holstein plus the states of Oldenburg, Braunschweig and Schaumburg-Lippe as well as northern exclaves of Waldeck and the Province of Hesse-Nassau. Capital: Hannover
- The Hanseatic Cities (
Hansestädte) of Hamburg, Bremen and Lübeck would be merged into a single state, exchanging their various exclaves for suburban regions around Hamburg in a similar way to what eventually happened with the Greater Hamburg Act (or at least that's how it looks on my source map). Capital: Hamburg (I think)
- The Free State of Upper Saxony (
Freistaat Obersachsen), covering Saxony minus Löbau and Zittau, the Province of Saxony minus its northern and western regions, the Landkreis Hoyerswerda and the Free State of Anhalt. Capital: Leipzig
- The Free State of Thuringia (
Freistaat Thüringen), covering the various Thuringian states plus the
Regierungsbezirk of Erfurt from the Province of Saxony and the Landkreis Schmalkalden from the Province of Hesse-Nassau. Capital: Weimar
- The Free State of Hesse (
Freistaat Hessen), covering the Province of Hesse-Nassau apart from its various exclaves, the provinces of Starkenburg and Oberhessen from the People's State of Hesse, and the Landkreis Wetzlar from the Rhineland. Capital: Frankfurt
- The Free State of Westphalia (
Freistaat Westfalen), covering the Province of Westphalia plus the Free State of Schaumburg-Lippe. Capital: Münster
- The Free State of the Rhineland (
Freistaat Rheinland), covering the Province of the Rhineland minus its Wetzlar exclave as well as the Birkendorf exclave of Oldenburg, the left-bank parts of Hesse and the Palatinate from Bavaria. Capital: Köln
- The Free State of Baden (
Freistaat Baden), covering the Republic of Baden (unclear whether the style would've actually changed - I'd hope not). Capital: Karlsruhe
- The Free State of Württemberg (
Freistaat Württemberg), covering the People's State of Württemberg (again, unclear style) plus the Hohenzollern territory from Prussia. Capital: Stuttgart
- The Free State of Bavaria (
Freistaat Bayern), covering Bavaria apart from the Palatinate and including some Thuringian exclaves. Capital: Munich
The internal divisions are based on those of the German Empire (except in Thuringia), and would probably not have looked like this. Mecklenburg's insane feudal mess would be particularly unlikely to survive reorganisation. The
Regierungsbezirke are mostly guesswork on my part.
Now, as it turned out, the state governments were mostly quite happy to rule the areas they ruled, and opposed Preuß' reorganisation proposal almost unanimously. In the face of this resistance, Preuß backed down, and the Weimar Constitution that was eventually passed by the Assembly left the boundaries as they were and required three-fifths of voters and majorities of the electorate in referendum to change them. The only changes that were made were the unification of the Thuringian states (except Coburg, which joined Bavaria) in 1920 and the annexation of Waldeck into Prussia in 1929.
The Weimar Constitution had, I think it's fair to say, a lot of issues. But this is one of the less talked-about ones, and one has to wonder what would've happened if Preuß had gotten his ideas through. The Free State of Prussia was usually stronger for the Weimar Coalition than the nation as a whole, and its government (led by Otto Braun of the SPD) frequently clashed with Hindenburg's right-wing national government. It was eventually suspended entirely (using another questionable clause of the Weimar Constitution) after the
Preußenschlag of 1930, paving the road to the emergency governments of the early 30s and eventually the Nazi takeover. If Prussia had been broken up into parts, no individual state would've gotten near its strength, and perhaps that would've speeded along the demise of Weimar democracy, or perhaps the more functional units envisioned by Preuß would've made the country slightly more governable.