Possibly the swiftest route to your roots.
Irish genealogy website directory.
www.bigenealogy.com/articles/ellisisland.htm
Description:
From 1892 to 1924, more than 22 million immigrants, passengers, and crew members came through Ellis Island and the Port of New York. Many of these were from the United Kingdom. The ship companies that transported these passengers kept detailed passenger lists, called "ship manifests."