Mo. Rev. Stat. § 79.470

For all ordinance violations the board of aldermen may impose penalties not exceeding a fine of five hundred dollars and costs, or ninety days' imprisonment, or both the fine and imprisonment. Where the city and state have a penalty for the same offense, the board shall set the same penalty by ordinance as is set by statute, except that imprisonments, when made under city ordinances, may be in the city prison or workhouse instead of the county jail.