St. Louis City and St. Louis County are two separate governments, not one nested inside the other. The City of St. Louis sits outside the county’s boundaries and functions as its own county-equivalent, so when comparing St. Louis City vs. County you’re comparing two full sets of courts, tax collectors, police departments, election boards, and school systems that happen to share a name and a region. Which one you deal with depends entirely on the address, and mailing addresses alone won’t tell you.
How to Tell Which One Your Address Is In
The U.S. Postal Service uses “St. Louis” for addresses on both sides of the line, and zip codes starting with 631 exist in both jurisdictions. That means your mail label is not a reliable answer. The City of St. Louis runs an online address validator that confirms whether a specific address falls within city limits.1City of St. Louis. Address Validation Check before you file a tax return, register to vote, apply for a building permit, or record a deed. Sending paperwork to the wrong jurisdiction means starting over.
A quick orientation: the county wraps the city on the north, west, and south, and the Mississippi River forms the eastern edge of both. The county contains 88 separate municipalities, from small villages to cities like Florissant and Chesterfield, and Clayton serves as the county seat.2City of St. Louis. City Government Structure If you live in one of those 88 municipalities, you’re dealing with your local city government, the county government, and possibly special taxing districts, all at the same address.
Taxes You’ll Pay Differently
The tax gap is the difference residents notice first, and it catches people off guard when they move across the line.
Earnings Tax
The City of St. Louis charges a one percent earnings tax on anyone who lives in the city or works within its limits, no matter where the employer is based.3City of St. Louis. Earnings Tax Department St. Louis County has no equivalent tax. State law requires city voters to reauthorize the tax every five years, and they most recently renewed it in April 2026 with roughly 85 percent voting yes.
Remote work has complicated the rules. If you live outside the city but work for a city employer, the tax applies to days you physically work inside city limits, and any portion of a day counted as work inside the city counts as a full city workday. Non-residents who had the tax withheld for days they actually worked elsewhere can file Form E-1R for a refund, but the employer has to verify the out-of-city days, and refund claims are barred one year after the original due date.4City of St. Louis. Individual Earnings Tax Information The city does not grant filing extensions on earnings tax returns.
Sales Tax
Rates vary sharply across the region. As of 2026, the combined sales tax rate in St. Louis City is 9.679 percent. The base rate in unincorporated St. Louis County is 7.738 percent, but individual municipalities and special taxing districts stack on top of that, and some commercial corridors in the county land close to 12 percent.5Missouri Department of Revenue. Sales and Use Tax Rate Tables The rate follows the exact address of the transaction, not just the city name or zip code.
Property Taxes
The City of St. Louis publishes a combined property tax rate that was $7.9593 per $100 of assessed value for the most recent available year, with commercial property paying an additional surcharge.6City of St. Louis. Property Tax Rates County property tax rates depend on the municipality and school district, so two homes a mile apart can have meaningfully different bills. The city and county keep separate assessor’s offices and separate collectors of revenue, so a new homeowner has to make sure the payment goes to the right one.
Courts and Jury Duty
The city and county operate independent judicial circuits. St. Louis City is the 22nd Judicial Circuit,7St. Louis Circuit Court. Jury Duty and St. Louis County is the 21st Judicial Circuit.8St. Louis County Courts. Home – St. Louis County Courts – 21st Judicial Circuit Each has its own courthouse, its own prosecutor, and its own jury pool. A lawsuit filed in the wrong circuit will be dismissed or transferred.
Jury duty follows the same divide. If you live in the city, you can only be called into the 22nd Circuit, where jurors must be city residents, U.S. citizens, at least 21 years old, and able to read and understand English.922nd Judicial Circuit Court of Missouri. Jury Duty County residents serve exclusively in the 21st.
Police, Elections, and Schools
Police
The St. Louis Metropolitan Police Department serves only the City of St. Louis. The St. Louis County Police Department is a separate agency that patrols unincorporated county areas and contracts with some municipalities that don’t run their own force. Many of the 88 municipalities have their own local police as well. A 911 call routes to different dispatchers depending on which side of the line the caller is on, and officers from one jurisdiction don’t respond to routine calls in the other.
Elections and Voter Registration
Two separate boards of election commissioners run elections and handle voter registration. The city’s board manages all public elections within city limits.10City of St. Louis. Board of Election Commissioners for the City of St. Louis The county’s board does the same for county residents.11St. Louis County Government. Board of Elections If you move from one to the other, you have to re-register with the correct board. Your old registration does not transfer.
Schools
St. Louis Public Schools is a city-only district. St. Louis County contains more than 20 separate school districts, each with its own tax levy, administration, and boundaries. The Special School District of St. Louis County operates across all of the county’s districts, running technical schools and providing special education services.12Special School District Of St. Louis County. Home The city district has no relationship to any county district, and moving a student across the city-county line means enrolling somewhere entirely new.
Why They’re Separate
Voters approved the split in 1876, in what locals still call the “Great Divorce.” City leaders wanted out of subsidizing county services and wanted full control over urban governance, and the freeholders who drafted the plan intended the new boundaries to be permanent.13St. Louis Magazine. St. Louis’ Great Divorce: A Complete History of the City and County Separation and Attempts to Get Back Together They got that part right. While other American cities annexed their suburbs through the twentieth century, St. Louis could not, and the county’s population eventually outgrew the city’s several times over.
The Missouri Constitution recognizes St. Louis as “both a city and as a county,”14Missouri Revisor of Statutes. Constitution of Missouri Article VI Section 31 – Recognition of City of St. Louis which is why the city runs its own Recorder of Deeds, Assessor, Collector of Revenue, and Sheriff. It’s the only city in Missouri that operates its own county-level offices.2City of St. Louis. City Government Structure Every dollar collected by the city stays in the city; nothing flows to the county. Today, the City of St. Louis covers 66 square miles with roughly 280,000 residents, while St. Louis County spans about 524 square miles with more than one million people.
Will They Ever Merge
The Missouri Constitution provides a path. Article VI, Section 30(a) lets voters consolidate the two governments, extend the county to absorb the city, annex county territory into the city, or adopt other combined-governance plans, but any proposal has to come from a Board of Freeholders and pass separate majority votes in both the city and the county.15Justia Law. Missouri Constitution Article VI Section 30a – Powers Conferred
The most recent serious attempt, Better Together, launched in 2013 and proposed a statewide constitutional amendment rather than the local freeholder process. Opposition was intense, including from African American officials in both jurisdictions who argued a merger would dilute Black political power, and the effort collapsed in 2019 after the coalition’s pick for interim mayor pleaded guilty to federal corruption charges. No active proposal has gained ground since. For now, the two governments are staying separate, and any address in the region belongs firmly to one or the other.