Interestingly, Ellis Island serves as an enclave of New York inside New Jersey. Though it falls on the New Jersey side of the state line, it was resolved between a compact of the states that New York would govern the islands in the Bay and Hudson. The Federal Government chose it as the site for an immigration station to replace Castle Clinton which it viewed as corrupt and inefficient.

The first immigration building on Ellis Island opened on January 1, 1892. In 1897 the original wooden building was destroyed by fire. The replacement building, designed by the firm of Boring and Tilton, is a French Renaissance Revival style structure of red brick with limestone trim. It opened in December of 1900 and was soon followed by a number of related buildings, including kitchen, laundry, power, and hospital facilities.

When the station opened in 1892, fewer than 20,000 people passed through the island a year. This was the result of an economic depression. By 1905 nearly one million people a year were immigrating to the United States. During its peak years (1905-1914) more than 5000 immigrants were seen every day, and it is estimated that more than 12 million people were processed through the immigration station at Ellis Island during its tenure.

The immigrants that entered were subjected to medical and psychological evaluations to deem fitness to enter the country, however, relatively few were sent back (~1%.) The station was expanded with multiple buildings to allow greater processing capacity, including an infectious disease ward. In doing so, Ellis Island followed Boring and Tilton's design standards to build the new additions.

The Black Tom explosion in 1916 (set off by German Agents to sabotage allied munitions) damaged the entire complex and resulted in the addition of the famous Guastavino tiled ceiling for the following renovation.

By 1924 the number of immigrants passing through the island had dramatically decreased due to restrictive legislation. Ellis Island was downgraded to a detention center for those about to be deported, it had gone from being the first thing that immigrants saw when they came to America to the last thing that they would see. In November 1954, the Immigration and Naturalization Service shut down their offices on Ellis Island and moved to a new location in Manhattan.