Where to Send Form N-600?
Form N-600, Application for Certificate of Citizenship, is the USCIS form that must be filed by individuals who acquire or derive US citizenship from their parents and by the individuals who become US citizens by the action of law, to obtain US citizenship certificates. A variety of supporting documents must be submitted and copies of birth certificates, passports, naturalization certificates or citizenship certificates, of your US citizen parents or your parent who is a US citizen, must be mailed along with your application for a US citizenship certificate, as proof.
Likewise, applications that are filed without the form filing fee may not be considered and this is one of the top reasons why the USCIS rejects applications. If you mail Form N600 without the filing fee, it will be returned to you and you will have to file the form again with the fee. Hence, do not forget to pay the required form filing fee, $600, along with your petition and you can use a money order or a check to pay the fee. Members the US armed forces and veterans need not pay the form filing fee but they must pay the required form filing fee if they are filing Form N-600 for their children. $550 must be paid as filing fee, if you are filing Form N-600 for an adopted child.
Along with Form N-600, you can also file Form G-1145, ENotification of Application/Petition Acceptance and if you file this form, USCIS will send you text messages or emails after accepting your Form N-600. USCIS has now published a new format of Form N-600 and the look and feel of Form N600 has been changed and the new form is easy to complete as it comes with step by step instructions. Currently USCIS accepts editions of Form N-600 dated 04/08/2013 and this form can be completed online and the completed forms must be mailed to the USCIS Phoenix Lockbox facility.
You will have to mail your petition to the following address.
US Postal Service (USPS)
USCIS P.O. Box 20100
Phoenix, AZ 85036
USPS Express Mail/Courier:
USCIS
Attn: Form N600
1820 E. Skyharbor Circle S
Suite 100
Phoenix, AZ 85034
Source: www.uscitizenship.info/blog