Mo. Rev. Stat. § 21.290

Notice of intention to apply for the enactment of local or special laws shall be published in each county or incorporated city or town to be affected by the local or special law, by advertisement in some newspaper, if one is published in the county or incorporated city or town, and if there is no newspaper published in the county or incorporated city or town, by posting ten written or printed handbills in ten public places in the county or incorporated city or town, one of which shall be posted on the courthouse door.