The State of New York passed a law in 1824 that required the master of a vessel arriving in New York from another country or state to provide a detailed report on every person brought into the Port of New York with the intention of proceeding to the City of New York. The master was required to post security for the maintenance of immigrants who became wards of the city, and the master was required to remove any noncitizen whom the mayor deemed likely to become a ward. George Miln (defendant), a master of a vessel, was assessed $15,000 as a penalty for violating the law. The mayor of New York City (plaintiff) sued the master to recover the penalty. The question of whether the law was valid under the United States Constitution was ultimately certified to the United States Supreme Court.