What changed
The neighbourhood investigation has been in U.S. law since 1952, in section 335(a), but was abandoned around 1991, when the immigration agency of the day shifted to relying on FBI criminal checks. A first revival came by memorandum in August 2025.
On 25 August 2026, USCIS issued Policy Alert PA-2026-10 and rewrote chapters 1 to 3 of part B of volume 12 of the Policy Manual, the handbook its officers follow. The new rule is direct: absent a waiver, the investigation applies to everyone and is generally carried out and completed before the interview. And it applies immediately, both to new applications and to those already waiting.
What the neighbourhood investigation is
It is an inquiry carried out by a USCIS investigator, who identifies themselves as such and speaks to people who know you personally. The stated aim is to gather information about your conduct, where you live, your reputation and your ties to the community, and to check what you wrote on the N-400. It covers at least the five years before the application, but USCIS may go further back and also investigate outside the United States, if it considers it necessary.
| Where the investigator may go | Whom they may speak to |
|---|---|
| In the neighbourhood of the homes where you lived | Neighbours, landlords, local shopkeepers, residents' association representatives |
| At your workplace | Bosses, managers, colleagues, administrative staff |
| At your business, if you have one | Partners, employees, clients, contractors |
The list of what they may look into is long: family situation, including marriages and divorces; social activities, associations and habits; jobs, periods out of work and businesses; financial obligations; schools you attended; your reputation in the community; criminal record; military service in the United States or abroad; trips abroad; where you live and have lived; your credibility; and what the manual calls attachment to the United States, that is, your loyalty and attitude towards the country and the Constitution.
How to seek a waiver: the reference letters
USCIS may waive the investigation, case by case, and the guidance points to a concrete route: filing at least two reference letters together with the N-400 may help that decision. The letters are optional, but the text says that not filing them, or refusing to, may contribute to the decision to investigate, as may failing to answer a request for further documents on the point.
One caveat the guidance itself makes, and it is reassuring: the absence of the letters, on its own, does not justify concluding that you lack the required good moral character. And for those naturalizing through the military routes in sections 328 and 329 of the immigration statute, service in the armed forces counts in the waiver decision.
Who may write: preferably U.S. citizens who know you personally, such as neighbours, bosses, colleagues and business partners. Letters from family members and close relatives are not considered. Each letter must include:
- The writer's full name, address, telephone and email, with a statement and document showing U.S. citizenship or immigration status.
- Their relationship with you and how long they have known you.
- Concrete examples or observations of honesty, integrity and involvement in the community.
- An express statement about your moral character and about your attitude towards the United States and the Constitution.
The checking of information at the interview
The same update reinforces, on the basis of section 335(b), the checking of what you declared: before and during the interview, the officer verifies addresses, jobs, education, family details, criminal record and your immigration history.
If something adverse comes up about you
The guidance preserves an important safeguard: if USCIS intends to deny your application on the basis of information obtained in the investigation, it must notify you clearly and give you an opportunity to respond. The investigator may request the investigation at any time before the oath, including after the interview. And you may still attend the interview accompanied by a lawyer or authorized representative.
Checklist before filing the N-400
- Gather at least two reference letters from people who know you personally, preferably U.S. citizens and never family members, with all the elements listed above.
- Check that addresses, jobs and dates for the last five years line up across the N-400, your documents and what the people around you know.
- Keep proof of where you lived and where you worked in that period.
- Be aware that an investigator identified as USCIS may approach neighbours, colleagues or business partners: this is now a normal part of the process.
- If there is any sensitive point in your history, such as long absences from the country, court cases or discrepancies in records, talk to a lawyer before filing.
Sources
- USCIS Policy Manual, volume 12, part B, chapter 2, Background Investigation and Security Checks, effective 25 August 2026.
- USCIS Policy Manual, volume 12, part B, chapter 3, Naturalization Examination, effective 25 August 2026.
- USCIS, Policy Alert PA-2026-10, Investigations and Examinations for Naturalization Eligibility, 25 August 2026.
- USCIS, Policy Memorandum PM-602-0189, Resumption of Personal Investigations of Aliens Applying for Naturalization (INA 335(a)), 22 August 2025, as cited in PA-2026-10.
- Immigration statute, sections 335(a), 335(b), 318, 328 and 329; and 8 C.F.R. part 335.
Updated 29 August 2026, based on the Policy Manual guidance that took effect on 25 August 2026. The guidance is recent and may be changed, expanded or suspended by a court.