New York Harbor that contains a museum and former

Mass detentions and deportations

Immigrants being inspected, 1904
Ellis Island's use as a detention center dates from World War I, when it was used to house those who were suspected of being enemy soldiers.^{[137][146][145][326]} During the war, six classes of "enemy aliens" were established, including officers and crewmen from interned ships; three classes of Germans; and suspected spies.^[327] After the American entry into World War I, about 1,100 German and Austrian naval officers and crewmen in the Ports of New York and New London were seized and held in Ellis Island's baggage and dormitory building.^[326] A commodious stockade was built for the seized officers.^[328] A 1917 New York Times article depicted the conditions of the detention center as being relatively hospitable.^[329]
Anti-immigrant sentiments developed in the U.S. during and after World War I, especially toward Southern and Eastern Europeans who were entering the country in large numbers.^[330][331] Following the Immigration Act of 1924, primary inspection was moved to New York Harbor, and Ellis Island only hosted immigrants that were to be detained or deported.^[155][156] After the passage of the 1924 act, the Immigration Service established multiple classes of people who were said to be "deportable". This included immigrants who entered in violation of previous exclusion acts; Chinese immigrants in violation of the 1924 act; those convicted of felonies or other "crimes of moral turpitude"; and those involved in prostitution.^[332]
During and immediately following World War II, Ellis Island was used to hold German merchant mariners and "enemy aliens"—Axis nationals detained for fear of spying, sabotage, and other fifth column activity.^[333] When the U.S. entered the war in December 1941, Ellis Island held 279 Japanese, 248 Germans, and 81 Italians removed from the East Coast.^[334] Unlike other wartime immigration detention stations, Ellis Island was designated as a permanent holding facility and was used to hold foreign nationals throughout the war.^[335] A total of 7,000 Germans, Italians and Japanese would be ultimately detained at Ellis Island.^[64]
The Internal Security Act of 1950 barred members of communist or fascist organizations from immigrating to the United States. Ellis Island saw detention peak at 1,500, but by 1952, after changes to immigration laws and policies, only 30 to 40 detainees remained.^[17][64] One of the last detainees was the Indonesian Aceh separatist Hasan di Tiro who, while a student in New York in 1953, declared himself the "foreign minister" of the rebellious Darul Islam movement and was subsequently stripped of his Indonesian citizenship and held as an "illegal alien".^[336]