File this form with the correct fees to the Nebraska Service Center. There are two different P.O. Box addresses:
If you are filing Form I-140 concurrently with Form I-485:
USCIS Nebraska Service Center
P.O. Box 87485
Lincoln, NE 68501-7485
If you are filing only Form I-140:
USCIS Nebraska Service Center
P.O. Box 87140
Lincoln, NE 68501-7140