N.D. Cent. Code § 24-05-08
Whenever the board of county commissioners of any county bordered by a state line deems it for the best interests of such county to open and improve a highway on said state line, it may negotiate with the proper officials of the adjoining county or state, and may make contracts or agreements pertaining to the opening up of such state line and the construction of a highway thereon. If the board of county commissioners deems it proper, it may agree with the officials of the adjoining county or state for the allotment of the highway on said state line, and may assume the obligation of construction and maintenance of certain parts of the said highway in return for the assumption of like obligations by the officials of the adjoining county or state as to a like portion of the state line forming the boundary of the said county.
N.D.C.C. § 24-05-08