Here is an overview of how Germany’s borders changed after World War I, designed to be clear and understandable for a Year 9/10 (14-year-old) history student.

The Big Picture – Treaty of Versailles (1919)

After losing World War I, Germany was forced to sign the Treaty of Versailles.1 The winners (Britain, France, and the USA) wanted to make sure Germany could never start a war again. To do this, they took away about 13% of Germany’s land in Europe and all of its overseas colonies.

This meant Germany lost about 6-7 million people and huge amounts of coal and iron production.

 

1. Changes in the WEST (France & Belgium)

The main goal here was to punish Germany and protect France from future attacks.

  • Alsace-Lorraine: This was a wealthy region on the border that Germany had taken from France in 1871.5 It was returned to France.

    • Why it mattered: It was rich in iron ore and was a matter of national pride for the French.

  • Eupen and Malmedy: These two small districts were given to Belgium.

  • The Rhineland: This wasn’t taken away, but the German army was banned from the area (demilitarized) to create a “buffer zone” for France.

The Saarland: This area was rich in coal. It was taken from Germany and placed under the control of the League of Nations (an early version of the UN) for 15 years. France was allowed to take all the coal from this region as “payment” for war damage.

2. Changes in the East (Poland and Lithuanis)

The changes here were the most painful for Germany because they split the country in two.

  • The Polish Corridor (West Prussia): A large strip of land was given to the newly created country of Poland so they could have access to the sea.

    • The Consequence: This cut Germany in two. The German province of East Prussia was now an island, separated from the rest of Germany by Polish land.15 This made Germans incredibly angry.

  • Danzig (Gdańsk): This was a major port city with a mostly German population.16 Instead of being German or Polish, it became a “Free City” run by the League of Nations. Poland was allowed to use the port for trade.

  • Upper Silesia: This was a rich industrial area. After a vote (plebiscite) by the locals, it was split between Germany and Poland.

  • Memel: A strip of land on the northeastern border was eventually taken by Lithuania.

3. Changes in the NORTH (Denmark)

  • Northern Schleswig: The people living here were given a vote (plebiscite) on whether they wanted to be German or Danish. The northern part voted to join Denmark, while the southern part stayed German.

Why did they draw the borders this way?

There were three main reasons the borders were moved:

  1. Punishment: To weaken Germany so it could not fight another war.

  2. Self-Determination: This was the idea (pushed by US President Woodrow Wilson) that different nationalities (like Poles or Danes) should have their own countries rather than being ruled by Germany.

  3. Security: France wanted strong borders (like the Rhine river) and allies in the East (like a strong Poland) to surround Germany.

The Result: “The Bleeding Borders”

For Germans in the 1920s, these border changes were humiliating.

  • Families were separated: People suddenly found themselves living in a different country (Poland or France) even though they spoke German.

  • Economic Ruin: Losing the coal fields in the Saar and Silesia made it very hard for Germany to pay its debts.

  • Resentment: The “Polish Corridor” splitting Germany became a major source of hatred.25 Adolf Hitler later used this anger to gain power, promising to “rip up” the Treaty of Versailles and unite Germany again.