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5 Major Ports
"Most passengers entering the United States between the mid-19th and mid-20th centuries disembarked at one of five major ports: New York, Philadelphia, Boston, Baltimore, and New Orleans. If you do now know where your ancestor landed, most likely it is one of the first three. But people entered America at many other places: small cities up and down the coasts had ports, and people crossed at several Mexican and Canadian border points."
--From: Pennevaria, Katherine. Genealogy: A Practical Guide for Librarians. Lanham, MD: Rowman & Littlefield, 2015, page 94.