N.D. Cent. Code § 40-02-02

Prior to the commencement of any proceedings to incorporate territory as a municipality, the persons intending to submit the petition for incorporation shall cause a census of the resident population of the territory to be taken not more than sixty days previous to the time when the petition is submitted to the board of county commissioners as provided in this chapter. The census shall show the name of every elector and of every head of a family residing within the territory on that day and the number of persons then belonging to that family, and the census shall be verified by the affidavit of the person taking it.