In Policy Alert PA-2026-10, issued Aug. 25, 2026, USCIS ended the general waiver of the personal investigations authorized by INA § 335(a) — the "neighborhood investigations" legacy INS had abandoned by 1991.
Unless USCIS waives it in a given case, the investigation now applies to every naturalization applicant and is generally completed before the interview is scheduled: a USCIS investigator may interview neighbors, landlords, employers, coworkers, and business associates, covering at least the five years before you filed. The guidance is effective immediately and applies to N-400s already pending, not only to new filings.
USCIS also said applicants may voluntarily submit character reference letters — preferably at least two, from U.S. citizens who are not relatives — and that it weighs them when deciding whether to waive the investigation.
If you have an N-400 on file or are preparing one, talk to us about whether to submit reference letters and about what the people around you would likely be asked.