A. LPR at Time of Filing and Naturalization
In general, an applicant for naturalization must be at least 18 years old and must establish that he or she has been lawfully admitted to the United States for permanent residence at the time of filing the naturalization application.  See INA 101(a)(20) and INA 334(b). See 8 CFR 316.2(a)(2). An applicant is not lawfully admitted for permanent residence in accordance with all applicable provisions of the INA if his or her LPR status was obtained by mistake or fraud, or if the admission was otherwise not in compliance with the law.  See INA 318. See Matter of Koloamatangi, 23 I & N Dec 548, 550 (2003). See Estrada-Ramos v. Holder, 611 F.3d 318, (7th Cir. 2010). See Mejia-Orellana v. Gonzales, 502 F.3d 13 (1st Cir 2007). See De La Rosa v DHS, 489 F.3d 551 (2nd Cir 2007). See Savoury v. U.S. Attorney General, 449 F.3d 1307 (11th Cir 2006). See Arellano-Garcia v. Gonzales, 429 F.3d 1183 (8th Cir 2005). See Monet v. INS, 791 F.2d 752 (9th Cir. 1986). See Matter of Longstaff, 716 F.2d 1439, 1441 (5th Cir. 1983).
In determining an applicant’s eligibility for naturalization, USCIS must determine whether the LPR status was lawfully obtained, not just whether the applicant is in possession of a Permanent Resident Card (PRC). If the status was not lawfully obtained for any reason, the applicant is not lawfully admitted for permanent residence in accordance with all applicable provisions of the INA, and is ineligible for naturalization even though the applicant possesses a PRC.
An applicant must also reside continuously in the U.S. for at least five years as an LPR at the time of filing,  See Chapter 3, Continuous Residence [12 USCIS-PM D.3]. though the applicant may file his or her application up to 90 days before reaching the five-year continuous residence period.  See Chapter 6, Jurisdiction, Place of Residence, and Early Filing [12 USCIS-PM D.6].
B. Conditional Residence in the General Requirements (INA 316)
A conditional permanent resident (CPR) filing for naturalization under the general provision on the basis of his or her permanent resident status for five years  See INA 316(a). must have met all of the applicable requirements of the conditional residence provisions.  See INA 216. CPRs are not eligible for naturalization unless the conditions on their resident status have been removed because such CPRs have not been lawfully admitted for permanent residence in accordance with all applicable provisions of the INA.  See INA 216 and INA 318. Unless USCIS approves the applicant’s Petition to Remove the Conditions of Residence (Form I-751), the applicant remains ineligible for naturalization.  See Part G, Spouses of U.S. Citizens [12 USCIS-PM G]; Part H, Children of U.S. Citizens [12 USCIS-PM H]; and Part I, Military Members and their Families [12 USCIS-PM I], for special circumstances under which where the applicant may not be required to have an approved petition to remove conditions prior naturalization.
1. Nationals of the United States
The law provides an exception to the LPR requirement for naturalization for non-citizen nationals of the United States. Currently, persons who are born in American Samoa or Swains Island, which are outlying possessions of the United States, are considered nationals of the United States.  See INA 101(a)(29) and INA 308.
A non-citizen national of the United States may be naturalized without establishing lawful admission for permanent residence if he or she becomes a resident of any State  See INA 325. See 8 CFR 325.2. Non-citizen nationals may satisfy the residence and physical presence requirements through their residence and presence within any of the outlying possessions of the United States. and complies with all other applicable requirements of the naturalization laws. These nationals are not “aliens” as defined in the INA and do not possess a Permanent Resident Card (PRC).  See INA 101(a)(20).
2. Certain Members of the U.S. Armed Forces
Certain members of the U.S. armed forces with service under specified conditions are also exempt from the LPR requirement.  See Part I, Military Members and their Families, Chapter 3, Military Service during Hostilities (INA 329) [12 USCIS-PM I.3].
D. Documentation and Evidence
USCIS issues a PRC to each person who has been lawfully admitted for permanent residence as evidence of his or her status. LPRs over 18 years of age are required to have their PRC in their possession as evidence of their status.  See INA 264(e). The PRC contains the date and the classification under which the person was accorded LPR status. The PRC alone, however, is insufficient to establish that the applicant has been lawfully admitted for permanent residence in accordance with all applicable provisions of the INA.  See Section A, LPR at Time of Filing and Naturalization [12 USCIS-PM D.2(A)].