Ellis Island Database Online
You can search for New York passenger arrivals here from 1892-1924. The site was later updated and now includes 1820-1957 so it extends beyond the Ellis Island years. Ellis Island was operating as an immigrant processing center from 1892-Jun 1897 and Dec 1900-1924. There are approximately 65 million total records in this database. The site was opened on 17 April 2001. Note that United States citizens and many of the first and second class passengers did not have to take the ferry over to Ellis island. However they were still recorded on the passenger lists and generally these arrivals should be in the Ellis Island Database. Tip: always try alternate spellings of the name(s) you are searching for. Sound out the name and try to think of ways someone hearing it might have spelled it. Passenger lists for the Ellis Island period can also be searched online at Family Search:
What About Ports Other Than New York?
If your ancestor arrived at a US port other than New York. See...
Year of immigration to America is given in the 1900, 1910, 1920 and 1930 census records. You can use this information to help narrow down your search.
Sigmund Freud and Carl Jung in the Ellis Island database...
Sigmund Freud and Carl Jung can be found in the Ellis Island database because they traveled together to New York in 1909. They did not immigrate to the United States and they were not processed at Ellis Island because they traveled first class. Their ship, the George Washington, arrived in New York from Bremen, Germany on August 29, 1909. Carl and Sigmund are listed as passengers #26 and #27 respectively on the ship manifest, which you can view online at FamilySearch here: Sigmund Freud (and Carl Jung) New York Passenger List
name: Jung, Carl
marital status: M
last residence: Swiss Nacht
name: Freud, Sigmund
marital status: M
last residence: Austria Wien (Vienna)
Sources: National Archives Microfilm Roll #T715-1324 (Passenger and Crew Lists of Vessels Arriving at New York, NY, 1897-1957), Vols. 2918--2919, Aug. 28-29, 1909.
Many other famous people made the trip from abroad to New York. See who you can find.