One thing that nearly all Americans with 19th century Irish ancestry have in common is that their ancestor(s) came to the USA on ships. Irish emigration to America started almost as soon as the first colonists set foot on these shores.
However, their numbers were relatively small for the first 200 years of the nation’s history. In the early 19th century, a tidal wave of Irish immigration began that lasted nearly a century! Most people in America today who have Irish ancestors have at least one direct ancestor who came to America during this explosive period of growth.
Nearly every ship that left the United Kingdom, from whatever port, carried a ship manifest with it.
This was a list of the passengers aboard the ship.
Most of the manifests were saved as important public records, and can be invaluable to family historians searching out their Irish roots. Most ship manifests included the name and age of each person traveling, and often included other important information such as occupation, other family members traveling on the same ship, point of departure, and point of arrival in America. A few manifests even include information on what the immigrant planned to do once on American soil! As you can see, this is all information that anyone searching for Irish families would covet for their own family trees.
If you know what year your ancestor came to America, you’ll have a much easier time finding the ship manifest you need. Immigrants who were in the USA in 1880 and were recorded in the census of that year were asked their date of arrival in the USA, so be sure to check the 1880 census for this information if you know your ancestor was here at that time. If you don’t know the date of arrival, you can do a search by name, or by port of departure or arrival in some cases, by making use of one of the several online databases that provide members access to ship manifests.
If your ancestor came through Ellis Island on arrival (and not everyone did), then you can access those records at http://www.ellisisland.org/.
Ancestry.com and the Origins Network currently provide the largest databases of ship manifests of Irish immigrants, so if you’re researching your Irish ancestry, these two sites could be very important in your research.