Entries in late 19th and early 20th century immigrant passenger manifests often include cryptic number and letter codes. Most genealogists simply look past them. Learn how to interpret these codes and what significant details they can reveal about your ancestor’s immigration and naturalization experience. Discover additional information about aliens who were detained or deported. This presentation is heavily illustrated with examples from New York and Philadelphia alien passenger lists and the handout includes a glossary of the terms, codes, and abbreviations found on these manifests.