St. Louis
St. Louis is not in St. Louis County
St. Louis City is an independent city. That changes where you look for assessor, collector, earnings tax, and vehicle paperwork.
St. Louis can fool you the moment a form asks for county. The City is not a municipality inside St. Louis County; it handles county-style jobs through City offices.
That split shows up fast in tax and property errands. The City Assessor handles assessment and property records for St. Louis addresses inside the City. The City Collector of Revenue handles real estate tax, personal property tax, water-refuse bills, and earnings and payroll taxes for the City. A St. Louis mailing address outside the City is a different track.
Use the boundary first, then the office. City address means City assessor or collector. County address means St. Louis County offices, even if the postal address still says St. Louis. This small geography check can save a bad receipt search or the wrong tax office.
References
Where this fits: this note belongs to St. Louis City. See every local note for the county on its page.