Ellis Island was first called into service as a Federal immigration station in 1890 by President Benjamin Harrison. From 1855 to 1890 immigrant processing was conducted at Castle Garden in the Battery and served as the processing station for the state of New York.
Most immigrants arrived in the United States at New York harbor because this was the most popular destination for steamship companies. However, there are 36 states in the U.S. that have records from their ports of immigrants who responded to the call of freedom and the promise of a better life. Some of the other cities that welcomed America's newest citizens were Boston, Philadelphia, Baltimore, San Francisco, Savannah, Miami, and New Orleans.
Many times a genealogist will not know which port to search for possible immigration records. Ellis Island's web site has made a preliminary search of their records quite easy. At http://www.EllisIland.org you can search through the records of immigrants, view passenger record or the ship's manifest. If you do not find your immigrant ancestor in these records, the next step would be to expand your search to surrounding ports, focusing on those ports closest to where your ancestor resided.
It is said that between 1892 and 1924, more than 27 million people came to America from all over the world and that at least 20 million of them were welcomed into America at Ellis Island. With odds like these you would think it would be easy to find the person you're looking for in the records at Ellis Island. However, that is not always the case. Many families faced the dilemma of one family member being turned away after the others had been admitted into the United States. The decision to either stay together and return to their native country or separate and part of the family remain in the States was one faced by many hopeful immigrants.