Your N-400 direct filing address depends on where you live. USCIS routes paper naturalization applications to one of four Lockbox facilities — Elgin, Illinois; Phoenix, Arizona; Dallas, Texas; or Chicago, Illinois — based on the state or territory listed as your residence on the form. Military applicants use a separate Chicago address no matter where they live. If you file online through your USCIS account, no mailing address applies.
How USCIS Decides Where Your Application Goes
The residential address you write on the N-400 is the only factor. Your field office, your prior addresses, and where you were originally admitted as a permanent resident do not change the Lockbox assignment. USCIS publishes the current state-by-state routing on its direct filing addresses page.1U.S. Citizenship and Immigration Services. Direct Filing Addresses for Form N-400, Application for Naturalization
Check that page immediately before mailing, not weeks ahead. USCIS reassigns states between Lockboxes from time to time, and an address that was correct earlier in the year may not be correct now. Mailing to the wrong Lockbox can mean your package is returned to you, and there is no guarantee USCIS will forward it to the right facility.2U.S. Citizenship and Immigration Services. Lockbox Filing Information
Each Lockbox has two addresses: a P.O. Box for U.S. Postal Service mail and a street address for FedEx, UPS, or DHL. These are not interchangeable. A USPS package sent to the courier street address, or a FedEx package sent to the P.O. Box, will fail delivery or be returned.
The Four Lockbox Addresses
Elgin Lockbox — Eastern States
Use the Elgin Lockbox if you live in Connecticut, Delaware, the District of Columbia, Florida, Georgia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, South Carolina, Vermont, Virginia, or West Virginia.1U.S. Citizenship and Immigration Services. Direct Filing Addresses for Form N-400, Application for Naturalization
- USPS: USCIS, Attn: N-400, P.O. Box 4060, Carol Stream, IL 60197-4060
- FedEx, UPS, or DHL: USCIS, Attn: N-400 (Box 4060), 2500 Westfield Drive, Elgin, IL 60124-7836
Phoenix Lockbox — Western and Southern States, U.S. Territories, and Armed Forces Addresses
Use the Phoenix Lockbox if you live in Alabama, Alaska, American Samoa, Arizona, California, Colorado, the Commonwealth of the Northern Mariana Islands, Guam, Hawaii, Idaho, Kansas, Kentucky, the Marshall Islands, Micronesia, Minnesota, Mississippi, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oregon, Palau, Puerto Rico, South Dakota, Tennessee, the U.S. Virgin Islands, Utah, Washington, or Wyoming. This Lockbox also handles applicants with Armed Forces addresses in the Americas, Europe, or Pacific.1U.S. Citizenship and Immigration Services. Direct Filing Addresses for Form N-400, Application for Naturalization
- USPS: USCIS, Attn: N-400, P.O. Box 21251, Phoenix, AZ 85036-1251
- FedEx, UPS, or DHL: USCIS, Attn: N-400 (Box 21251), 2108 E. Elliot Rd., Tempe, AZ 85284-1806
Dallas Lockbox
Use the Dallas Lockbox if you live in Arkansas, Louisiana, Oklahoma, or Texas.1U.S. Citizenship and Immigration Services. Direct Filing Addresses for Form N-400, Application for Naturalization
- USPS: USCIS, Attn: N-400, P.O. Box 660060, Dallas, TX 75266-0060
- FedEx, UPS, or DHL: USCIS, Attn: N-400 (Box 660060), 2501 S. State Hwy 121 Business, Suite 400, Lewisville, TX 75067-8003
Chicago Lockbox — Midwestern States
Use the Chicago Lockbox if you live in Illinois, Indiana, Iowa, Michigan, Missouri, Ohio, or Wisconsin.1U.S. Citizenship and Immigration Services. Direct Filing Addresses for Form N-400, Application for Naturalization
- USPS: USCIS, Attn: N-400, P.O. Box 4380, Chicago, IL 60680-4380
- FedEx, UPS, or DHL: USCIS, Attn: N-400 (Box 4380), 131 S. Dearborn, 3rd Floor, Chicago, IL 60603-5517
Military Applicants Use a Separate Address
If you are applying based on current or former military service, or as the spouse, parent, or child of a deceased service member, your application goes to a dedicated military address at the Chicago Lockbox. This holds regardless of the state you live in.1U.S. Citizenship and Immigration Services. Direct Filing Addresses for Form N-400, Application for Naturalization
- USPS: USCIS, Attn: Military N-400, P.O. Box 4446, Chicago, IL 60680-4446
- FedEx, UPS, or DHL: USCIS, Attn: Military N-400 (Box 4446), 131 S. Dearborn, 3rd Floor, Chicago, IL 60603-5517
Military applicants living outside the United States who also need to file for an initial parole document should review the USCIS filing addresses page for the additional routing that applies in that situation.1U.S. Citizenship and Immigration Services. Direct Filing Addresses for Form N-400, Application for Naturalization
Fee Waiver and Reduced-Fee Applicants
Requesting a fee waiver on Form I-912 or a reduced fee on Form I-942 does not change your filing address. You mail the paper N-400, together with the waiver or reduced-fee form and supporting financial documentation, to the same Lockbox that matches your state of residence.3U.S. Citizenship and Immigration Services. I-912, Request for Fee Waiver4U.S. Citizenship and Immigration Services. I-942, Request for Reduced Fee
One boundary matters here: if you are requesting either a fee waiver or a reduced fee, you cannot file online. Only paper filings are eligible, so the Lockbox address applies to you.5U.S. Citizenship and Immigration Services. Forms Available to File Online
Filing Online Instead
If you are paying the full fee, you can file the N-400 through your USCIS account at uscis.gov and skip the Lockbox question entirely. The online fee is $710, compared to $760 for paper.6U.S. Citizenship and Immigration Services. Application for Naturalization5U.S. Citizenship and Immigration Services. Forms Available to File Online Submission produces an instant electronic confirmation, and any later requests for evidence can be handled by uploading documents directly through your account.7U.S. Citizenship and Immigration Services. Tips for Filing Forms Online
What Happens at the Lockbox
The Lockbox is not where your case is decided. Staff scan your documents, verify the fee, and run initial acceptance checks. If the package passes, they deposit the payment, generate a receipt notice, and forward the file to the USCIS service center or field office that will handle your interview. If the package cannot be processed at the Lockbox you sent it to, it may be forwarded to the correct facility, but there is no guarantee; a package that cannot be routed is returned to the address on the form.2U.S. Citizenship and Immigration Services. Lockbox Filing Information
Because the Lockbox uses high-speed scanners, ship with a service that provides tracking and delivery confirmation. USPS certified mail, FedEx, and UPS all give you a date-stamped record of when the package arrived, which is the evidence you will want if a dispute ever arises about whether or when USCIS received your application.
If You Move While Your N-400 Is Pending
Once your application is in, changing your address does not change where you originally filed, but you are legally required to notify USCIS within 10 days of any move.8USCIS. Chapter 10 – Changes of Address Update your address through your USCIS online account or by filing Form AR-11. Missed notices from a stale address can cost you an interview slot, a biometrics appointment, or an oath ceremony date.