Hi Judith -

There is excellent information about the US naturalization process
at the NARA website.
http://www.archives.gov/genealogy/naturalization/naturalization.html

Generally, a person had to live in the US for 2 yrs before being eligible
to file a declaration of intent, then wait an additional 3 years before the
process could be finalized. Over the years, these requirements were
changed, and there were different rules for women and minors.

A good book on the subject is They Became Americans, by Loretto Szucs.

Not all people who filed a declaration of intent followed through
to become a citizen. My 2nd great grandfather never became
a citizen although he did file a declaration 1899.

As far as the dates given by our ancestors in census and other
records, we can't always rely on them to be correct.

The best we can do is use these dates as a guideline to finding
the passenger records, then branch out systematically to other
years and other locations. Unfortunately, there were many ports
in addition to Ellis Island where they could have arrived. Although
there are many records on line now, there are also many that are
only on film at NARA, and others which have been lost.

My great grandmother arrived in Providence RI around 1908, but
the records for the Port of Providence at this time do not exist
[or at least they have not been found yet]

Lisa