20 C.F.R. § 416.1610
(a) What you should give us. You can prove that you are a citizen or a national of the United States by giving us—
(b) How to prove you are an interim citizen of the United States if you live in the Northern Mariana Islands. As a resident of the Northern Mariana Islands you must meet certain conditions to prove you are an interim citizen of the United States. You must prove that you were domiciled in the Northern Mariana Islands as required by section 8 of the Schedule of Transitional Matters of the Constitution of the Northern Mariana Islands, or that you were born there after March 6, 1977. By “domiciled” we mean that you maintained a residence with the intention of continuing that residence for an unlimited or indefinite period, and that you intended to return to that residence whenever absent, even for an extended period. You must also give us proof of your citizenship if you are a citizen of the Trust Territory of the Pacific Islands of which the Marianas are a part.
(1) You can prove you were domiciled in the Northern Mariana Islands by giving us—
(2) You can prove that you are a citizen of the Trust Territory of the Pacific Islands by giving us—
(c) What to do if you cannot give us the information listed in paragraph (a) or (b). If you cannot give us any of the documents listed in paragraph (a) or (b), we may find you to be a citizen or a national of the United States if you—
(2) Give us any information you have which shows or results in proof that you are a citizen or a national of the United States. The kind of information we are most concerned about shows—
[47 FR 3106, Jan. 22, 1982, as amended at 62 FR 59813, Nov. 5, 1997]