Derivative Citizenship

If your immigrant ancestor has a "derivative" citizenship, then what likely happened is that they were a minor when their father naturalized or they became a citizen upon their marriage to a man who was already a citizen.

Naturalization law is complex and slightly confusing, but if your immigrant ancestor indicates in a census or other record that he was naturalized and you cannot find a record of his or her naturalization, consider the possibility that they obtained citizenship status through the father's naturalization or their marriage.

And naturalization law and procedure has changed over time--make certain you know what the law and procedure was at the time your ancestor was alive and naturalized.

Of course, like everything else...there are exceptions.