Mo. Rev. Stat. § 321.070
Immediately after the filing of such petition or any amended petition changing the boundaries, the court wherein such petition is filed or the judge thereof in vacation shall, by order, fix a time and place not less than thirty days nor more than sixty days after the petition is filed for a hearing thereon, and thereupon the circuit clerk shall cause notice by publication to be made of the filing of the petition and the pendency of the action and of the time and place of the hearing thereon. The circuit clerk shall also forthwith cause a copy of the notice to be mailed by United States registered mail to the governing body of each municipality having territory within the proposed boundaries of the proposed district, and to the county commission of each county in which the proposed district lies.
§ 321.070, RSMo