Also, can anyone point me to a thread about mailing the N-400. On USCIS pages, I can't find any information that says I can mail it Registered/Return Receipt requested or Express, or anything else like that. Is it ok to send it in this way so that I am sure that it has been received? I could not find this topic in the forum. Perhaps I am looking for it wrong. I just don't want to send it in a matter that will result in it not getting through, but sending it regular first class mail just does not seem like enough assurance.
Send it to the Texas or Phoenix lockbox unit, depending on your state/DO.
The instructions are clear in the N-400 instructions guide.
I have sent mine with USPS using certified mail so that I can track the status. You don't need return receipt. If you send it by Express mail, it may reach there a day earlier than regular post.
Where to File :
If you currently reside in Alaska, Arizona, California, Colorado, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, North Dakota, Ohio, Oregon, South Dakota, Utah, Washington, Wisconsin, Wyoming, Guam or the Commonwealth of the Northern Mariana Islands, send your application to the USCIS Lockbox Facility at:
USCIS
P.O. Box 21251
Phoenix, AZ 85036
For express/courier deliveries, use:
USCIS
Attn: N-400
1820 E Skyharbor Cicle S, Floor 1
Phoenix, AZ 85034
If you reside in Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Mississippi, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Vermont, Virginia, West Virginia, Puerto Rico or the U.S. Virgin Islands, send your application to the USCIS Lockbox Facility at:
USCIS
P.O. Box 299026
Lewisville, TX 75029
For express/courier deliveries, use:
USCIS
Attn: N-400
2501 S State Hwy 121, Bldg. #4
Lewisville, TX 75067
All naturalization applicants filing under the military provisions, section 328 or 329, should file their application at the Nebraska Service Center regardless of geographic location or jurisdiction. Please send your application to:
Nebraska Service Center
P.O. Box 87426
Lincoln, NE 68501-7426
For express/courier deliveries, use:
Nebraska Service Center
850 S Street
Lincoln, NE 68508