You become a citizen at the time you take the Oath of Allegiance to the U.S at a U.S. federal district court. Sometimes it takes place at the USCIS local office. In some States it is possible to take the Oath of Allegiance at the same day as your interview. If you prefer a later date or if this alternative is not available, USCIS will inform you of the date with a “Notice of Naturalization Oath Ceremony” (Form N-445).