Mo. Rev. Stat. § 230.070

The county highway commission shall have absolute jurisdiction and control over all highways constituting a part of the county highway system, and shall hold title in fee to the right-of-way thereof, and no other officer, board or commission, except as in this chapter specifically provided, shall have or exercise any authority or jurisdiction over any of such highways. The roads constituting the county highway system shall be known and designated as "county highway".