In this lecture, attendees will examine how the unique waterway system of the Great Lakes served as a primary engine for westward expansion and settlement. The session provides a methodical overview of the geographical and historical development of these inland “seas,” from early fur trade routes and the Straits of Mackinac to the engineering marvels of the Welland Canal and the St. Lawrence Seaway. Participants will learn how to navigate specialized maritime records, including Great Lakes passenger lists at the National Archives (NARA) and unique collections at the Alpena County George N. Fletcher Public Library. By understanding the functional impact of steamships and canal travel on migration patterns, researchers will gain a comprehensive framework for tracing ancestors who utilized these vital waterways to establish new lives in the American Midwest and Ontario.