Mo. Rev. Stat. § 137.195: County commissions to procure plats from United States land office.

Each county commission of this state shall procure from the register of the United States land office and keep on file plats of all townships and parts of townships in their respective counties, showing the county lines on a scale sufficiently large to show the sections and parts of sections, by their legal subdivisions, and all lands subject to taxation at that time, and also all private land claims with the name of the original claimant, the number of the survey and the number of acres.