The Inquiry on Polish and Czechoslovak borders 1919

[Peterski]

Here is what the Inquiry suggested pertaining to Polish borders after WW1:

https://en.wikipedia.org/wiki/The_Inquiry







Map (Danzig, all of Upper Silesia and part of East Prussia were to be Polish):



^^^
Gdańsk-Malbork-Iława-Działdowo-Mława-Warsaw railway line was to become Polish:



As was the Masurian Lake District which provides a border which is easy to defend:

The impact of the glacier on the evolution of terrain in Warmia-Masuria

[Peterski]

And what they suggested pertaining to Czechoslovak borders after WW1:

https://archive.org/stream/MyDiaryAt...n247/mode/2up/