The United States has been keeping passenger lists since 1820. These lists can be essential sources of information on immigrants arriving in the U.S. between 1820 and 1865, but to use them effectively one must understand how and why they were created. Background The number of immigrants coming into the United States and the information collected about them has always been influenced by world events and by national immigration policy. During, and immediately after the American Revolution, immigration to the New World slowed to a trickle. After all, who wants to immigrate to a country in the middle of a war? Within a decade of the end of our Revolutionary War, a revolution broke out in France, and this war affected much of western Europe. Many European ports were blockaded, which obviously limited departures, and hence arrivals in America. The defeat of Napoleon and the end of the war in 1815 unleashed a torrent of emigration from Europe, much of it to the United States. More immigrants arrived than ever before. This sudden increase in passengers and the opportunity to make more money put pressure on ship owners to carry as many passengers per trip as possible. The result was overcrowded ships and bad travel conditions. Government Requires Lists of Arrivals Alarmed at this situation, the recently formed U.S. government took over jurisdiction of immigration to the still new United States. In 1819, Congress passed a law regulating the maximum number of passengers allowed per ship, based on its total tonnage. Although the allocations were not very restrictive and did little to improve the conditions of the passengers, the law also mandated the keeping of a list of arrivals. These lists are truly a Godsend for today's family historians. The Bureau of Customs was charged with the keeping of these lists, hence the lists from 1820 through about 1891 (the ending dates vary by port) are called the "Customs Passenger Lists." The bureau provided blank forms to the shipping companies, which the captains (usually their mates) prepared on board. These forms were then submitted to the collector of customs at the port of arrival. Eventually, these lists, or the ones that survived the ravages of time, ended up in the custody of the National Archives, where they have been microfilmed for preservation and improved access. The law also required that copies and abstracts of the list be made for the State Department. With the loss of some of the original lists, these copies and/or abstracts are an invaluable source for filling those gaps. Therefore, when the original lists were microfilmed, the National Archives included available copies and abstracts in the microfilms. Thus we have a fairly complete collection of documents identifying more then 20 million persons who arrived during this time period.