Mo. Rev. Stat. § 137.200: Plats or maps lost — duty of county commissions.

In any county where land plats or maps have been lost or destroyed, the county commission of such county shall procure others to supply the places of those so lost or destroyed; and where any county commission fails to procure such maps or plats at least sixty days before the time for commencing the assessment in any year, it shall be the duty of the assessor of such county to procure them, to be paid for by the county.