What should you do if the ancestry trail you are following leads you outside the boundaries of the United States? How can you trace an ancestor’s path of immigration into the United States or find evidence of travels abroad? Passenger Lists are one obvious source of information.

Until the middle of the 20th century the vast majority of travel in and out of the United States was by sea. Following the successful voyage of the Mayflower in 1620, a steady stream of passengers from the Old World began arriving on the shores of America.

Passenger lists that have survived are a mixed bag. Although most outbound passenger lists were not preserved, passenger lists from incoming vessels may contain a treasure trove of detailed information including the passenger’s appearance, occupation, a place residence, birth year, names of relatives awaiting them in the United States, and other details. Other passenger lists may contain only sketchy information, in some cases only a first and last name, making it difficult to do more than guess at an ancestor’s probable journey.

According to some estimates about 40 percent of Americans can trace their ancestors to Ellis Island. Between 1892 and 1924, about 20 million immigrants to the U.S. were processed at Ellis Island. Those records are available online at the American Family Immigration History Center (www.ellisislandrecords.org).

Cyndi’s List (www.cyndislist.com/ships.htm) casts a wider net, linking to a variety of shipping-related websites, including The Ships List (www.theshipslist.com), which offers passenger lists, immigration reports, newspaper records, shipwreck information, ship pictures, ship descriptions, shipping-line fleet lists and more.

Another starting point for immigration research is the National Archives, which offers a useful list of resources at (http://www.archives.gov/genealogy/immigration/index.html#links).