Because they were run out of much of Western Europe during the Middle Ages and somewhat tolerated by the Blyat Empire, where they merely suffered pogroms and were forced into the Pale of Settlement.
Ashkenazic Jews or Ashkenazim,[a] constitute a Jewish diaspora population that emerged in the Holy Roman Empire around the end of the first millennium CE.[8] They traditionally spoke Yiddish[8] and largely migrated towards northern and eastern Europe during the late Middle Ages due to persecution.
The “Poland-Lithuania” that most of these migrations went to, at the time included large portions of present day Ukraine, Belarus and Russia. The regions with the highest Jewish populations prior to WW2, seem to match the borders of the polish-lithuanian commonwealth before it was partitioned by their neighbours in the 18th century. https://en.m.wikipedia.org/wiki/Partitions_of_Poland
Why were there so many Jewish people living in Poland and Russia?
Because they were run out of much of Western Europe during the Middle Ages and somewhat tolerated by the Blyat Empire, where they merely suffered pogroms and were forced into the Pale of Settlement.
Had to look up Blyat.
They were in occupied, foreign territory. No German people, no rules and no law. That would be my explanation.
Jewish people were living in Poland and Russia in 1939 because it was occupied, had no rules, and had no law?
Ashkenazic Jews or Ashkenazim,[a] constitute a Jewish diaspora population that emerged in the Holy Roman Empire around the end of the first millennium CE.[8] They traditionally spoke Yiddish[8] and largely migrated towards northern and eastern Europe during the late Middle Ages due to persecution.
https://en.m.wikipedia.org/wiki/Ashkenazi_Jews
The “Poland-Lithuania” that most of these migrations went to, at the time included large portions of present day Ukraine, Belarus and Russia. The regions with the highest Jewish populations prior to WW2, seem to match the borders of the polish-lithuanian commonwealth before it was partitioned by their neighbours in the 18th century. https://en.m.wikipedia.org/wiki/Partitions_of_Poland