If you want to sponsor someone for a family-based green card, you need to provide proof of a U.S. domicile in your Affidavit of Support (Form I-864). How Can I Prove U.S. Domicile?In this post, we'll explore examples of proof of US domicile and the documents required to establish proof of domicile. Copies of bank statements, automobile registration, or other registered Allegheny County property. A Certificate of Residence(PDF, 13KB) form is required as part of recording all deeds transferring property ownership. This guide will clarify what domicile is, how to establish it, and the documentation you need for proof of domicile. Typically, in order to claim US domicile, the Affidavit of Support sponsor must be residing in the United States. For approval of incapacitated person's claim where any action has been instituted, see. Allegheny County Civil and Family Division Rule 2206.