Mo. Rev. Stat. § 64.010: County planning commission authorized (first class charter counties).

In all counties of the first class, except counties of the first class not having a charter form of government, the county commission is authorized and empowered to provide for the preparation, adoption, amendment, extension or carrying out of a county plan and to create by order a county planning commission with the powers and duties as set forth in sections 64.010 to 64.160.