All of this is from a book:
Upton Sinclair: The Lithuanian Jungle,
by Gierdrius Subacius
This discusses Sinclair’s initial sources and investigates the reasoning behind his ultimate choice for Lithuanian characters.
Click here to see an interactive Google map that shows the whole area where the story took place.
The outlined perimeter of the Google map links to ANOTHER map actually from the era.
I have added many annotations and it is worth a quick look.