Dear Ms. Barrick,
Thank you for posting your request on History Hub!
We suggest that you review these Genealogy: Passenger Arrival List Research Tips and not limit your search efforts to only the Boston port. There are numerous ways that individuals could enter the United States from Europe such as via a ship to a larger number of coastal ports or over land from Canada, etc. Ship passenger arrival lists were a requirement beginning in 1820, but that does not guarantee that person was recorded or that the list still exists. Many of the passenger lists have been digitized and are name-searchable online at Ancestry.com and FamilySearch.org. Keeping records of border crossings from Canada were not required in the mid-1800s. Therefore, if your great grandparents entered the U.S. via Canada, there may not be documentation of their crossing.
If you have an idea of where the vessel may have departed on the European end, it could be useful to look at passenger departure lists. Because the Polish ports were predominantly freight ports, it was common for Polish emigrants to travel overland to Germany and depart through a port there like Hamburg. Therefore, we suggest that you check the German immigration data available on NARA’s Access to Archival Databases List of Series - Genealogy/ Personal History: Passenger Lists.
We hope this is helpful. Best of luck with your family research!
[Information provided by Elizabeth Burnes, Subject Matter Expert]