You can replace your lost citizenship certificate by filing Form N-565, Application for Replacement Naturalization or Citizenship Document, with the USCIS.
Form N-565 is usually filed with the USCIS if you have to replace a Naturalization Certificate, Certificate of Citizenship, Declaration of Intention or Repatriation Certificate which has been lost, mutilated, or destroyed. Additionally, this form is also used if your name has been changed by marriage or by court order after the citizenship document was issued and you need a document in the new name. But Form N-565 should not be filed to correct errors on the citizenship certificate unless they are USCIS errors.
To replace your lost citizenship certificate, you should prepare and mail the completed N-565 application package to the USCIS along with the appropriate filing fee and supporting documents. You will find all the information about the fees, the mailing address and supporting documents in the instructions page. If you make a mistake filling out your application, or with your filing fee or mailing address, your application will be returned to you.
When sending your application to replace your lost citizenship certificate, you should include two color photographs along with your supporting documents. The photograph should be taken within 30 days of filing this application. If the reason for filing form N-565 is to get a replacement of a mutilated document, you will have to attach the mutilated document and send it with your N-565 application. If your document is in a foreign language, make sure that it is accompanied by a certified, full English language translation that is complete and accurate. After you mail in your N-565 application to replace your lost citizenship certificate, the USCIS will check for completeness, such as including all the required documentation and the correct submission fee.
If you do not fill out the form completely, or have sent the application without the needed initial evidence, you will not establish a basis for eligibility and chances are that the USCIS may deny your application. If your application is not signed or not accompanied by the correct fee, the USCIS will reject it and send you a notice with the reason why you were denied. So make sure that your application is complete and that you submit the required supporting documents and the correct fee.
Once you have mailed the completed application along with the fees and supporting documents to the USCIS, you can expect to receive an Application Receipt Notice with a 13-character Application Receipt number within 30 days. This Receipt Notice acts as the proof that USCIS has received your application and that it is being processed. You can check the status of your application with the receipt number.
The USCIS officials may request more information or evidence when you appear at the USCIS office for an interview. Additionally, they may also request you to submit the originals of any document. Lastly, if everything is in order with your application, it will be approved and a replacement for the lost citizenship certificate will be issued. If your application is denied, the USCIS will notify in writing with the reason(s) why. The whole process takes an average of up to six months.