N.D. Cent. Code § 11-18-09
The recorder, when any deed, patent, mortgage, receiver's receipt, contract, notice of lis pendens, copy of decree, or other instrument affecting the title to, or creating a lien upon, any real estate within the county is filed in the recorder's office, shall write or stamp thereon immediately a document number. Document numbers shall commence with the number one in each county and shall follow consecutively in the order of filing of the various documents. Priority of the document number on an instrument shall be prima facie evidence of the priority of the filing thereof. When the recorder receives by mail or other like enclosure more than one instrument at a time, the recorder shall affix document numbers thereon in the order in which such instruments actually come to the recorder's hand on opening such enclosure, save that when more than one instrument is recorded from the same source at the same time, the recorder may follow such directions, if any, as the sender may give in such numbering.
N.D.C.C. § 11-18-09