Who Qualifies as a U.S. Citizen?

1. birth in the U.S.
2. birth to U.S. citizen parent anywhere
3. naturalization
4. naturalization of parents

Interestingly, many people born in other countries are pleasantly surprised to find they are already U.S. citizens, if anyone in a direct line of their ancestors was a U.S. citizen (such as a grandparent). There are various laws that deal with this, but if you believe that an ancestor was a U.S. citizen, it is definitely worth looking into.