Wilkes Barre / Scranton has quite a few . On the New Jersey side of the Delaware Trenton has a Polish district north of Rte #1. Further into NJ the town of Linden is mostly Polish .
In fact its a very small Russian/Lithuanian and Polish community of about 2/3 blocks just behind the lottery circle with a town next to Lawrenceville. There are lots of Polish stores/delis,travel agencies etc. Also I use to go there for Polish buffet only one in NJ I could find.
I had a business in linden,south wood ave where mostly the polish community is 2nd third generation.