OBTAINING CITIZENSHIP THROUGH PARENTS AND/OR GRANDPARENTS
Some foreign nationals have a claim to U.S. citizenship through birth abroad to U.S. citizen parents or through birth abroad to one U.S. citizen parent and one foreign parent. Some foreign nationals can even trace their claim to citizenship back to grandparents who were U.S. citizens.
For those interested in immigrating to the United States, it is always wise to check to see if one or more of your parents or grandparents are or were U.S. citizens. Depending on the year they were born, years they resided in the U.S. and when you were born, you may have a valid claim to U.S. citizenship of your own.
HELPFUL INFORMATION
Obtaining Citizenship Through Parents
Procedures for Determination of United States Nationality of a Person Abroad
Acquisition of Citizenship for Children Born Overseas (State Department)