In 1833 a state law was enacted requiring the captain of each vessel entering Baltimore to register the names of all immigrants and to pay $1.50 for each German or Irish immigrant over five years old. This law was the result of a decade of agitation over immigration fueled by the fear of disease, financial strain on local charities, and a large number of paupers; the intent of this law was to restrict immigration.

Eventually the funds derived from this tax went to relief agencies. Starting in 1834 two-fifths of this income was passed to the German and Hibernian Societies for assistance to German and Irish immigrants who composed the vast majority of the foreigners. After 1842 the remainder of the monies went to the Trustees for the Poor of Baltimore City and County. This system finally ended in 1875 when the United States Supreme Court ruled that such taxes were unconstitutional.

For more information on the history of these records see Richard J. Cox, "The Creation and Maintenance of Baltimore's Passenger Ship Lists by the Municipal Government, 1833-1866," Maryland Genealogical Society Bulletin 22 (Winter 1981): 2-9.