Where to send N-400 application through Priority Mail Signature Confirmation

[Ping Ting 0]

Hello members of this community, can you please guide me where to send N-400 application packet through priority mail with signature and delivery confirmation. While reading instructions they say for Illinois use following address

USCIS

P.O. Box 21251

Phoenix, AZ 85036

But then they say ,

...............................................................................

For express mail or commercial courier service, send at following address

USCIS

Attn: N-400

1820 E.Skyharbor Circle S Ste 100

Phoenix, AZ 85036

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Express mail is expensive one while priority mail is less costly , so I wanna send through priority mail signature confirmation, what should I do please help me.

People with successful stories please can guide me,

Thank You.

[livelife2dfullest 7]

Send it to the first address

[LA80 3]

If you gonna use Priority Mail, use the address no.1:

USCIS

P.O. Box 21251

Phoenix, AZ 85036

Express Mail kinda equals courier service (DHL, UPS, FedEx), but I do not think it is worth all that money, and you only gonna save a day or two as the regular mail is delivered within 3 days anyway.

I used the ordinary First Class, certified, with return receipt ("green card"), and it got there in two days. I could track the package online. The only "bad" thing is that I got NOA faster than that return receipt.