Mo. Rev. Stat. § 230.060
Whenever any county highway laid out and designated under the provisions of this chapter shall be over and along the route of any existing highway, it shall be the duty of the county commission, or other board or commission, having jurisdiction over such highway, to convey the same to the county highway commission, who shall thereafter have control and supervision thereover, and whenever any such county highway shall be laid out and designated through any special road district, or in counties under township organization, it shall be the duty of the commissioner of such special road district, or of the treasurer of such township, to pay over to the county highway commission, such proportion of the total road revenue arising therein as the mileage of said county highway within said special road district, or township, shall bear to the total number of road mileage therein.
§ 230.060, RSMo