Back in the interwar period, Poland was one of the most ethnically diverse countries in Europe. Minorities made up 31% of population. Ukrainians, Belarussians and Ruthenians were concentrated mostly in the East, Germans lived in the West and Lithuanians populated the northernmost counties. Poland has also a very large Jewish community, concentrated mostly in larger cities. Warsaw alone was home to over 300,000 Jews, making it the largest Jewish city in the world second only to New York City.

Kamień Koszyrski county in was the most non-Polish county, with just 7.05 percent citizens claiming speaking Polish at home, followed closely by Drohiczyn and Kosów counties with 7.06 and 7.16 percent population speaking Polish respectively, all three in Polesie Voivodeship. There were 68 majority-minority counties in Poland (out of 261) populated by 8.6 million people (or 27.1 percent of total population).

Ukrainian was the most common minority language, with 3.2 million speakers. Yiddish ranked second, with 2.5 million speakers.

Belarussian language was most commonly spoken in the Northeast, the area which now constitutes Belarus and Lithuania, and a tiny scrap that remained Poland. There are almost 50,000 Belarussians in Poland today.

Lithuanians were, and still are, a small minority in Poland. They were concentrated around Vilnus, a modern day capital of Lithuania and in 1931 a major Polish city.

Germans made a sizable minority in Greater Poland and Upper Silesia. Today, German speakers are the second largest minority in Poland.

Jews constituted a major part of Polish society and were present across the country. The Jewish population of Poland declined from over 3 million in 1939 to 7508 in 2011, with millions of Polish Jews perishing in the Nazi Holocaust.

Modern day Ruthenians identify as Ukrainians or Lemks, so there are no modern day statistics on that group.

Ukrainians were the largest minority group in Poland in 1931. In 2011, there were only about 30,000 Ukrainians in Poland, but that might change in light of the recent events in Ukraine.

“Local” language was the most commonly chosen one in Polesie voivodeship, a very poor and uneducated area.

There were 22 million Poles in 1931. Today, population of Poland is 38 million.

As the national boundaries shifter after World War II, many Poles had to leave their homes and move West.

This is a guest post by Szymon Pifczyk, who studies Business Analytics at the Katowice University of Economics in Poland. He is interested in cartography and demographics. He blogs at Arduous Trifles. You can reach Szymon at szypifczyk (at) gmail.com.