Except for the brief period from March 1803 to March 1806, no official registers of passengers leaving Irish ports were ever kept. The exception refers to lists contained in the so-called Hardwicke Papers, now located in the British Library, London. Altogether, some 4,500 passengers are identified in the 109 sailings recorded in the Hardwicke Papers--most cited with their all-important place of residence. Although Dublin was the most popular port of departure, the three northern ports of Belfast, Londonderry, and Newry accounted for 61% of the sailings. New York was far and away the most popular destination, with Philadelphia running a reasonable second. The Hardwicke lists, only fragments of which have ever appeared in print, as transcribed by Brian Mitchell now fill a significant gap in the records, since in many cases they will prove to be the only record of an ancestor's emigration to the U.S.