Mo. Rev. Stat. § 61.160: Appointment (second, third and fourth class counties).

The county commissions of each county in this state in classes two, three and four are hereby authorized and empowered to appoint and reappoint a highway engineer within and for their respective counties at any regular meeting, for such length of time as may be deemed advisable in the judgment of the commission. The provisions of sections 61.160 to 61.310 shall apply only to counties of classes two, three and four.