The Northern Irish port of Londonderry (here referred to as Derry) was the principal port of departure for Irish emigrants during the first half of the nineteenth century. The work at hand is an effort to enumerate the immigrant trade between Derry and the port of Philadelphia for that period of time. Mr. Adams, who combed through U.S. Customs Passenger Lists at the National Archives, the passenger manifests of the Cunard and Cooke shipping lines, and the civil parish emigration lists retained by the Public Record Office in Northern Ireland, in preparing this work, provides us with a list of 3,200 Ulster emigrants to Philadelphia between 1803 and 1850. Arranged alphabetically according to the head of the household–with other family members listed immediately under the head–the entries typically furnish the name of the emigrant, his/her age, town and county of origin, where given, year of emigration, and name of ship. Ulster Emigrants to Philadelphia, which commences with a concise overview of the causes of the emigration and concludes with an alphabetical checklist of townlands (addresses) and their associated counties in Ireland, is as complete a work on its subject as we are likely to have.