Mo. Rev. Stat. § 89.030: Zoning districts.

For any or all of said purposes the local legislative body may divide the municipality into districts of such number, shape, and area as may be deemed best suited to carry out the purposes of sections 89.010 to 89.140; and within such districts may regulate and restrict the erection, construction, reconstruction, alteration or use of buildings, structures, or land. All such regulations shall be uniform for each class or kind of buildings throughout each district, but the regulations in one district may differ from those in other districts.