Which countries had the largest Jewish communities in 1939 and what were their populations?

1. Where the big numbers come from — the global baseline

Postwar and modern demographic summaries commonly use a prewar world Jewish population of roughly 16.6 million for 1939; Israel’s Central Bureau of Statistics and news outlets cite this figure when contrasting today’s totals with pre‑Holocaust numbers ^{[2] [6]}. That global total is the anchor used by researchers and encyclopedias when listing which countries had the largest Jewish communities on the eve of war ^{[2] [7]}.

2. Largest Jewish communities in Europe in 1933–1939 — Poland, Soviet Europe, Romania

Holocaust Encyclopedia material identifies Poland as the largest European Jewish community with about 3,000,000 Jews (roughly 9.5% of Poland’s population at the time), followed by the European portion of the Soviet Union with about 2,525,000 and Romania with about 756,000 ^[3]. These three were the dominant centers of prewar European Jewry and together represented the bulk of the roughly 15–16 million Jews living worldwide in the 1930s ^{[3] [2]}.

3. National breakdowns exist but vary by source and year

Scholarly tables and archival compilations (for example AJYB and Jewish Data Bank material) provide country-by-country lists for 1937–1939; those datasets are the basis for many later summaries and maps, but different compilers use varying definitions (core Jewish population, country borders as of 1939, inclusion of partially Jewish persons) that change rankings and counts slightly ^{[4] [5]}. Available sources do not present a single universally agreed numeric table for every country in 1939 in the documents provided here ^{[4] [5]}.

4. Other large prewar communities outside eastern Europe

Although eastern Europe held the majority, other sizeable Jewish populations existed elsewhere. Contemporary reference pages and later encyclopedic summaries note that western European communities (for example in Germany, France, and the United Kingdom) and diaspora communities in the Americas were significant, but none matched Poland’s prewar scale; Germany’s Jewish population in 1933 was about 505,000, with urban concentrations such as Berlin (~160,000) ^[8]. Global overviews point to major communities later concentrated in the United States and, after 1948, Israel — but those postwar shifts reflect migration and losses during the Holocaust ^{[9] [10]}.

5. Why the numbers matter — accounting for the Holocaust and migration

The 1939 country-level totals are a snapshot taken immediately before Nazi conquest, deportations, mass murder, and large refugee movements that dramatically reshaped Jewish demographics. The Holocaust Encyclopedia and postwar population summaries document that European Jewish populations collapsed between 1939 and 1945 (for example Europe’s Jewish numbers fell from roughly 9.4 million to under 3 million in the immediate postwar period), underscoring that 1939 figures are best understood as “pre‑catastrophe” baselines ^{[3] [10] [9]}.

6. Limits, disagreements and how to interpret the sources

Different sources use slightly different totals: some cite ~16.6 million worldwide for 1939 ^{[2] [6] [7]}, while Holocaust Encyclopedia’s Europe‑focused table emphasizes the roughly 60% of world Jewry living in Europe and gives the country figures quoted above ^[3]. Compilers such as the AJYB/Jewish Data Bank provide more granular tables but rely on census years around 1937–1939 and on definitions ^[4]. Therefore, authoritative rankings (Poland first, European USSR second, Romania third) are stable across these sources, but precise counts for smaller countries and the global total display modest variation ^{[3] [4] [2]}.

7. If you want the country-by-country list

Detailed, downloadable country tables are available in historical demography compilations (AJYB / Jewish Data Bank) and research tables cited by modern scholars; those provide numeric estimates for 1937–1939 and are the proper next step if you need precise per‑country counts rather than rounded headline figures ^{[4] [5]}. Available sources do not supply a single, fully enumerated country list for 1939 in the set you provided here, so consult the AJYB/Jewish Data Bank tables referenced above for the most detailed breakdowns ^{[4] [5]}.

Summary verdict: multiple reputable sources agree on the headline: worldwide Jewish population on the eve of WWII ~16.6 million, with Poland (~3,000,000), the European USSR (~2,525,000), and Romania (~756,000) hosting the largest Jewish communities in Europe before the Holocaust ^{[2] [3]}.