[Docere]

As a general rule, in the Northeast and Midwest (as well as Toronto and Montreal in Canada), there were large Jewish immigrant populations a century ago.

In the South and West - DC, Florida, California etc. - Jewish populations are not usually the product of direct immigration, and were greatly outnumbered by domestic migration. Hence only a small minority of Jews in L.A., say, can trace their roots to Boyle Heights, for example.

In Britain, meanwhile, the Jewish population is much more concentrated in London nowadays than it was in the early 20th century. Manchester, Leeds and to some extent Glasgow had good sized Jewish populations.