22 C.F.R. §§ 51.42–51.44

Primary evidence of birth in the United States. A person born in the United States generally must submit a birth certificate. The birth certificate must show the full name of the applicant, the applicant's place and date of birth, the full name of the parent(s), and must be signed by the official custodian of birth records, bear the seal of the issuing office, and show a filing date within one year of the date of birth.

Secondary evidence of birth in the United States. If the applicant cannot submit a birth certificate that meets the requirement of paragraph (a) of this section, he or she must submit secondary evidence sufficient to establish to the satisfaction of the Department that he or she was born in the United States. Secondary evidence includes but is not limited to hospital birth certificates, baptismal certificates, medical and school records, certificates of circumcision, other documentary evidence created shortly after birth but generally not more than 5 years after birth, and/or affidavits of persons having personal knowledge of the facts of the birth.

General. A person born outside the United States must submit documentary evidence that he or she meets all the statutory requirements for acquisition of U.S. citizenship or non-citizen nationality under the provision of law or treaty under which the person is claiming U.S. citizenship or non-citizen nationality.