Mo. Rev. Stat. § 322.120: Applicability of law (Cass, Clay, Cole, Franklin, Lincoln, and St. Francois counties).

Except as otherwise provided by law, the provisions of sections 322.090 to 322.130 shall be applicable to all counties of class one and counties of class two which adjoin a county of the first class having a charter form of government or which are south of the Missouri River and border another second class county with a population of one hundred thousand or more inhabitants.