U.S. Citizenship and Immigration Services no longer uses local field offices to accept and process Applications for Certificate of Citizenship for adopted children (Form N-600 – unrelated to forms I-600 and I-600A). The fee is now $550 for adoption cases.  You should also print out the attached “Filing Tips” form.  Please now send your N-600 forms by U.S. mail to:

USCIS
P.O. Box 20100
Phoenix, AZ  85036

Express mail or couriers:

USCIS
Attn:  Form N-600
1820 E. Skyharbor Circle S
Suite 100
Phoenix, AZ  85034