Following the establishment of the Second Polish Republic after World War I and during the interwar period, the number of Jews in the country grew rapidly. According to the Polish national census of 1921, there were 2,845,364 Jews living in the Second Polish Republic; by late 1938 that number had grown by over 16 percent, to approximately 3,310,000, mainly through migration from Ukraine and the Soviet Russia. The average rate of permanent settlement was about 30,000 per annum. At the same time, every year around 100,000 Jews were passing through Poland in unofficial emigration overseas. Between the end of the Polish–Soviet War of 1919 and late 1938, the Jewish population of the Republic grew by nearly half a million, or over 464,000 persons.Yehuda Bauer, A History of the American Jewish Joint Distribution Committee 1929–1939. End note 20: 44–29, memo 1/30/39 (30th January 1939), The Jewish Publication Society of America, Philadelphia, 1974 Jews preferred to live in the relatively-tolerant Poland rather than in the Soviet Union and continued to integrate, marry into Polish Gentile families, to bring them into their community through marriage, feel Polish and form an important part of Polish society. Between 1933 and 1938, around 25,000 German Jews fled Nazi Germany to sanctuary in Poland.The Routledge Atlas of the Holocaust by Martin Gilbert, pp. 21. Relevant page viewable via Google book search

The Jewish community in Poland suffered the most in the ensuing Holocaust. From amongst the 6 million Polish citizens who perished during the occupation of Poland in World War II, roughly half (or 3 million) were Polish Jews murdered at the Nazi extermination camps of Auschwitz, Treblinka, Majdanek, Belzec, Sobibór, and Chełmno. Others died of starvation and maltreatment in the ghettos. Occupied Poland became the largest site of the Nazi extermination program since most of the targeted victims lived there. Only about 50,000–120,000 Polish Jews survived the war on native soil,Richard C. Lukas, Out of the Inferno: Poles Remember the Holocaust University Press of Kentucky 1989 - 201 pages. Pages 5, 13, 111; also in Richard C. Lukas, The Forgotten Holocaust: The Poles Under German Occupation, 1939-1944, University Press of Kentucky 1986 - 300 pages.Michael C. Steinlauf. "Poland.". In: David S. Wyman, Charles H. Rosenzveig. The World Reacts to the Holocaust. The Johns Hopkins University Press, 1996. along with up to 230,000 on Soviet soil.Laura Jockusch, Tamar Lewinsky, Paradise Lost? Postwar Memory of Polish Jewish Survival in the Soviet Union, full text downloaded from Holocaust and Genocide Studies, Volume 24, Number 3, Winter 2010. Soon after the war ended, Jewish survivors began to leave Poland in great numbers thanks to the repatriation agreement with the Soviet Union. Poland was the only Eastern Bloc country to allow free Jewish aliyah without visas or exit permits. The exodus took place in stages. Many left simply because they did not want to live in a communist country. Others did not wish to rebuild their lives where their families were murdered and instead joined their relatives abroad.

Polish independence movement As soon as the Polish independence movement took hold in 1912 to 1914 with the aim to put forth an armed struggle for sovereign Poland after a century of partitions, the main freedom organization was formed, Komisja Skonfederowanych Stronnictw Niepodległościowych, and served as an interim government. Polish Jews played a significant role in it such Herman Feldstein, Henryk Eile (future Lieutenant of the Polish Army), Samuel Herschthal, Zygmunt Leser, Henryk Orlean, Wiktor Chajes, who worked in its various sub-commissions. Also, Jews made substantial financial contributions to the formation of the Polish military fund, Polski Skarb Wojskowy.

Interwar period (1918–1939)

During World War I, while many other non-Polish minorities were ambivalent or neutral to the idea of a sovereign Polish state, Jews actively participated in the fight for Poland's independence between 1914 and 1918 – a significant number joining Józef Piłsudski at the famous Oleandry area in Kraków, among them Bronisław Mansperl-Chaber killed in 1915 as the First Lieutenant of 1st Brigade, Polish Legions. In Lwów, chaired by Maria Loewenstein, two existing Jewish Women's Associations united as Ognisko Kobiet, for the purpose of financial support and caring for the families of soldiers and their children. Representatives of the local Jewish merchant associations adopted a resolution declaring their participation in the struggle for Poland's independence and issued an appeal to the Jewish masses. Similar proclamations came from the Jewish youth organization Zjednoczenie.Zygmunt Zygmuntowicz, "Żydzi Bojownicy o Niepodleglość Polski", as excerpted at Forum Żydów Polskich from his book published 1939 in Lwów.

During the military conflicts that engulfed Eastern Europe at the time—the Russian Civil War, Polish–Ukrainian War, and Polish–Soviet War—many pogroms were launched against the Jews by all sides. A substantial number of Jews were perceived to have supported the Bolsheviks in Russia. They came under frequent attack by all those opposed to the Bolshevik regime. Just after the end of World War I, the West became alarmed by reports about alleged massive pogroms in Poland against Jews. American pressure for government action reached the point where president Woodrow Wilson sent an official commission to investigate the issue. The commission, led by Henry Morgenthau Sr., announced that the reports of pogroms were exaggerated, and in some cases may have even been fabricated. It identified eighty-nine major incidents in years 1918–1919, and estimated the number of victims at 200–300 Jews. Four of these were attributed to the actions of deserters and undisciplined individual soldiers; none were blamed on official government policy. Among the incidents, in Pinsk a Polish officer accused a group of Jewish communists of plotting against the Poles, shooting 35 of them. In Lviv (then Lemberg) in 1918, as the Polish army captured the city, hundreds of people were killed in the chaos, among them about 72 Jews. In Warsaw soldiers of Blue Army assaulted Jews on the streets, but they were punished by military authorities. When the Polish troops entered Vilnius in 1919, the first Lithuanian pogrom in modern city on Lithuanian Jews took place, as noted by Timothy Snyder, citing Michał Pius Römer. Many other events in Poland were later found to have been exaggerated, especially by contemporary newspapers like The New York Times, although serious abuses against the Jews, including pogroms, continued elsewhere, especially in the Ukraine. The result of the concern over the fate of the Jews of western Poland was a series of explicit clauses in the Paris Peace Conference protecting the rights of Jews in Poland.

Jewish and Polish culture The newly independent Second Polish Republic had a large Jewish minority—by the time World War II began, Poland had the largest concentration of Jews in Europe. According to the 1931 Polish census there were 3,130,581 Polish Jews measured by the declaration of their religion. Taking into account both population increase and the emigration from Poland between 1931 and 1939, there were around 3,474,000 Jews in Poland as of September 1, 1939 (approximately 10% of the total population). Jews were primarily centered in large agglomerations: 77% lived in the cities and 23% in the villages. In 1939 there were 375,000 Jews in Warsaw, or one third of the city's population.Street photo, prewar Warsaw, Poland Film and Photo Archive, Yad VashemMiła Street, Warsaw, prewar Poland Film and Photo Archive, Yad Vashem Only New York City had more Jewish residents than Warsaw. Jewish religious groups, political parties, newspapers and theatre thrived. Most Warsaw Jews spoke Yiddish, but Polish was increasingly used by the young who have not had a problem in identifying themselves fully as Jews, Varsovians and Poles. Polish Jews were entering the mainstream of Polish society, though many thought of themselves as a separate nationality within Poland. During the school year of 1937–1938 there were 226 elementary schools and twelve high schools as well as fourteen vocational schools with either Yiddish or Hebrew as the instructional language.Students at a Jewish School, Warsaw, prewar Poland Film and Photo Archive, Yad Vashem The YIVO (Jidiszer Wissenszaftlecher) Scientific Institute was based in Wilno before transferring to New York during the war. Jewish political parties, both the Socialist General Jewish Labour Bund (The Bund)The Bund Council in August 1937, Warsaw, Poland Film and Photo Archive, Yad Vashem as well as parties of the Zionist right and left wing and religious conservative movements, were represented in the Sejm (the Polish Parliament) as well as in the regional councils.

The Jewish cultural scene was particularly vibrant and blossomed in pre-World War II Poland.Tadeusz Piotrowski, Poland's holocaust: ethnic strife, collaboration with occupying forces. McFarland, p. 51. There were many Jewish publications and over 116 periodicals. Yiddish authors, most notably Isaac Bashevis Singer, went on to achieve international acclaim as classic Jewish writers, and in Singer's case, win the 1978 Nobel Prize in Literature. Other Jewish authors of the period, like Janusz Korczak, Bruno Schulz, Julian Tuwim, Jan Brzechwa (a favorite poet of Polish children) and Bolesław Leśmian were less well known internationally, but made important contributions to Polish literature. Singer Jan Kiepura was one of the most popular artist of that era and pre-war songs of Jewish composers like Henryk Wars or Jerzy Petersburski are still widely known in Poland today. In 1918 Julian Tuwim co-founded the cabaret, "Picador," and worked as a writer or artistic director with many other cabarets such as "Czarny kot" (Black Cat 1917–1919), "" (1919–1932), "Banda" The Gang and "Stara Banda" The Old Gang (1932–1935) and finally "Cyrulik Warszawski" (Barber of Warsaw 1935–1939). Marian Hemar also wrote for some of the mentioned cabarets.