Mo. Rev. Stat. § 47.190: Town may be laid off into lots.

If no town shall have been laid off at the place selected as the permanent county seat, the county commission shall order the same, or so much thereof as it shall deem expedient, to be laid off; or if such tribunal shall deem it expedient to lay off additional lots where a town shall have previously been laid off, it may order the same to be done, and in either case the commissioner of such county seat shall proceed to lay off such land, or so much thereof as such county commission shall direct, into lots, squares, avenues, streets, lanes and alleys, in such manner and under such regulations as such county commission shall prescribe, and make report thereof to such county commission, with a plat of the town, or part of a town, so laid off, which, if approved by such county commission, shall be deposited in the office of the recorder of the county, and by him carefully preserved and recorded.