Plan East - The Interbellum Polish-Soviet Border

The Interbellum Polish-Soviet Border

Poland's shared border with the Soviet Union was 1,412 kilometers long. By comparison, the border with Germany and its province of East Prussia was more than 20 percent longer, at 1,912 km. Neither border contained any major geographical obstacles, making defense very difficult.

In the north there was a flat, plain land with huge forests (e.g. Puszcza Nalibocka — the Wilderness of Naliboki). In addition, a major rail route connecting Moscow to Western Europe extended across the northern portion of the country. The areas major conurbation at the time was Wilno, located in the northeast corner of interbellum Poland.

The centre region of the country was primarily composed of a huge, sparsely populated swamp known as Polesie. This land had no roads and few rail lines. However, it held supreme strategic importance, as its landscape made possible a prolonged, organized defense. Neither Polesie nor the adjacent Volhynia contained any major urban centers.

The south, formerly a portion of the Galicia province of the Austrian Empire, was the most highly developed, with a high density of rail lines, growing industry (e.g., oil fields in Boryslaw), and the well-developed agriculture of Podolia. Lwów, one of the major urban centers of interbellum Poland, was located in this area. In addition, the Soviet border was marked by a natural obstacle — the Zbrucz river.

Virtually all Polish industrial and urban centers were located in the West. This made long-lasting defense possible, as a Soviet force would have taken up to several weeks to reach Upper Silesia, Warsaw, Kraków or Poznań. While devising Plan Wschód, Polish planners assumed cooperation and support would be forthcoming from Romania, which was Poland's main ally in the East.