Beginning in 1895, immigrants who arrived at Canadian seaports with the declared intention of proceeding to the United States were recorded and included in the immigration statistics.
Other alien arrivals at land borders began to be reported in 1906, and reporting was fully established in 1908 under authority of an act of February 20, 1907 (34 Stat. Not all aliens entering via the Canadian and Mexican borders were necessarily counted for inclusion in the immigration statistics.
In 1900 administration of the Chinese-exclusion laws was added. land borders was not required by early immigration acts.
Initially the Bureau retained the same administrative structure of ports of entry that the Customs Service had used. Thus, statistical treatment of Canadian and Mexican border immigrants at times has differed from that of other immigrants.
Arriving aliens who came into the United States for 29 days or less were not counted except for those who were either certified by public health officials, held for a board of special inquiry, excluded and deported, or were individuals in transit who announced an intention to depart across another land boundary or by sea.