St. Louis
In St. Louis County, the municipality layer is real
St. Louis County property can involve county records plus municipal occupancy, permit, inspection, or local rule layers.
St. Louis County has many municipalities, and the city or village layer can matter even when the county tax record is easy to find.
For a move or renovation, do not stop at the county assessor. Check the municipality for occupancy permits, rental rules, point-of-sale inspections, exterior work rules, and local fees.
The exact local rule is not the same in every municipality, so Missouri Porch treats this as a place-specific research item, not a single countywide answer.
References
Where this fits: this note belongs to St. Louis County. See every local note for the county on its page.