St. Louis County, Missouri business license guide
Last updated: October 5, 2026 | Next review: January 3, 2027
Starting a business in St. Louis County can be confusing because the right government depends on the exact address and the activity. Your location may be inside one of the county’s municipalities, in unincorporated St. Louis County, or in the separate City of St. Louis.
This guide separates the county, municipal, Missouri, and federal layers so you can find the right license, tax registration, zoning review, occupancy approval, food permit, or other step before you spend money.
Bottom line: does St. Louis County have a county business license?
Do not look for one universal St. Louis County business license that replaces every city license. The local map is split. A municipality may require its own business license. St. Louis County separately handles matters such as business personal property registration, merchant or manufacturer licensing, certain activity-specific licenses, unincorporated-county zoning, county building or occupancy functions, and public-health permits.
The County Assessor’s current registration form says businesses operating in St. Louis County must register with the Assessor’s office. It also says a merchant license is required for retail or wholesale sales and lists a $5 merchant/manufacturer license fee. That $5 is not a universal county business-license fee.
Your first job is to identify the government that controls the physical address. A mailing address that says “St. Louis” does not answer that question.
St. Louis County business changes: May 1–October 2, 2026
A new St. Louis County-specific LLC property affidavit rule took effect August 28, 2026. Missouri Revised Statutes section 347.048 now requires an LLC that owns and rents or leases real property, or owns unoccupied real property, in a county with more than one million inhabitants to file an affidavit with the county clerk only when both statutory conditions are met: the same property has more than two ordinance violations, and an attempt to resolve the violation with the LLC’s registered agent was unsuccessful.
The affidavit must identify at least one natural person with management control and responsibility for the property. A successor affidavit is due within 30 days after that person’s management responsibility ends, and the statute prohibits a filing fee. This is not a routine filing for every St. Louis County LLC and it is not a general business license. The statute directs the filing to the County Clerk. A dedicated public section 347.048 filing form was not located during this review, so an affected LLC should confirm the current submission method with the St. Louis County Clerk/County Council administration before filing. Read Missouri Revised Statutes section 347.048.
Start here: confirm which government controls your address
- Separate St. Louis County from the City of St. Louis. The City of St. Louis has been an independent city since 1876 and is not part of St. Louis County. If your business is inside the City of St. Louis, use the City of St. Louis business license process and our St. Louis, MO business license guide.
- Check whether the St. Louis County address is inside a municipality. Use the St. Louis County Geospatial Data Center, property lookup, and municipal boundaries data. Then confirm with the municipality or County if the boundary is unclear.
- Build a short license map. List the local business license, County Assessor registration, zoning/occupancy, food or other activity permit, Missouri entity/name/tax registrations, employer steps, and any professional license that applies to your business.
Do this before signing a lease or paying a filing company. The same postal city can contain addresses controlled by different local governments.
St. Louis County license, tax, and permit layer
St. Louis County government has several separate business-related roles. Do not treat one County office as the place for every license.
Business personal property and merchant/manufacturer licensing
The St. Louis County Assessor business registration form combines business personal property registration with an application for a merchant and/or manufacturer license. The current form says all businesses operating in St. Louis County must register with that office. Retailers and wholesalers should pay special attention to the merchant-license portion.
The form also asks for items such as Missouri Secretary of State registration, a Missouri sales-tax number when selling products, a No Tax Due certificate for retailers, and an occupancy certificate. These are separate requirements from the County Assessor filing itself.
County Revenue Licensing handles specific activities
The St. Louis County Department of Revenue Division of Licenses handles particular license categories. It should not be confused with a universal all-business license office.
One practical example is a street vendor selling food or beverages from a motor vehicle in the part of the county covered by County Code Chapter 812. The current St. Louis County street-vendor application requires written approval from the Department of Public Health before the license application is submitted. County Code Chapter 812 applies the street-vendor licensing rule to territory outside incorporated cities, towns, and villages.
Planning and zoning in unincorporated St. Louis County
The St. Louis County Department of Planning administers zoning regulations in unincorporated St. Louis County. Use the County’s zoning verification and compliance information to confirm whether the proposed use fits the property.
If the address is inside an incorporated municipality, start with that municipality’s zoning office instead. County departments may still have a separate role for particular building, health, utility, or technical matters.
Building, occupancy, and construction
For County-controlled work, review Commercial Building, Permits and Applications, and the County’s Commercial Occupancy guidance. Inside a municipality, verify whether the city, County, or another agency performs each review.
Food and restaurant permits
St. Louis County Public Health maintains Food and Restaurants, food permit applications, the St. Louis County Food Code, and temporary-event food information. A food permit is separate from a city business license, zoning approval, and the County merchant-license layer.
City and municipal business license layer
If the business is inside an incorporated St. Louis County municipality, check that municipality before opening. Local rules differ, and a city business license or occupancy approval does not replace the County Assessor, state tax, or regulated-industry steps.
Examples of municipal rules
| Municipality | What the current city guidance shows | Official route |
|---|---|---|
| Clayton | Commercial occupancy approval comes before the business-license application. Clayton has multiple business-license types, and the license year runs July 1 through June 30. | Clayton business license instructions |
| Florissant | Verify zoning and any special-use issue, obtain commercial occupancy/zoning approval, then complete the business-license process when required. The city uses its online permit portal for these steps. | Florissant permits and business licensing |
| Chesterfield | The city’s business area routes owners to licensing, opening-a-business, occupancy, signs, zoning, tax, and special-activity information. | Chesterfield business information |
These are examples, not countywide rules. If your address is in another municipality, use that municipality’s current process.
If your address is in the City of St. Louis
Stop using this county guide for the local license layer. The City of St. Louis is a separate independent city. Its License Collector business-license page describes the city process.
DBA, fictitious name, and business name layer
A Missouri fictitious name is a state filing, not a St. Louis County business license. The Missouri Secretary of State fictitious name FAQ says a person or business operating under a name other than its true name must register the fictitious name with the Secretary of State.
The current FAQ says online filing is available through Missouri Business Filings, the mail filing fee is $7, and a registration is effective for five years. It also says the filing does not give exclusive rights to the name. A DBA does not replace a municipality’s business license, zoning approval, tax registration, or professional license.
Missouri state registrations and taxes
Entity registration
If you form an LLC, corporation, or another entity that must register with Missouri, use the Missouri Secretary of State Corporations Division and its official online filing system. Entity formation creates or registers the entity; it does not prove that your address is approved for the business activity.
Missouri tax registration
The Missouri Department of Revenue Business Tax Registration page explains when to register for sales tax, employer withholding, corporate tax, and other state tax accounts. Businesses making taxable retail sales should verify the Missouri retail sales-tax license requirement before making sales. The Department also provides online business registration.
Employer registrations
If you hire workers, do not stop after getting an EIN. Check the Missouri Department of Revenue for employer withholding, the Missouri Division of Employment Security for unemployment tax, and the state new-hire reporting system.
- Use Missouri Business Tax Registration for employer withholding when required.
- Use UInteract employer information to register a new business for unemployment-tax purposes and manage the account.
- Use the Missouri New Hire Reporting Center. Missouri says newly hired employees must generally be reported within 20 calendar days.
Professional and occupational licenses
For regulated occupations, check the Missouri Division of Professional Registration or the correct state licensing agency. A city business license does not replace a state professional credential.
Federal EIN
If your business needs an Employer Identification Number, get it directly from the IRS EIN service. The IRS does not charge a fee for an EIN.
Zoning, home occupation, occupancy, building, fire, health, and industry permits
Zoning and home businesses
Home-business rules need special care because Missouri law now limits what local governments may require. Missouri Revised Statutes section 71.990 says a political subdivision may not prohibit a qualifying no-impact home-based business or require that business to obtain a local permit, license, variance, registration, or other prior approval simply to operate. The statute also bars a political subdivision from requiring commercial rezoning or a home-based-business license as a condition of operating a home business.
The protection is not unlimited. The business must fit the statutory no-impact conditions, including rules concerning occupancy, traffic, parking, where activity occurs, street visibility, and lawful goods or services. Local government may still use narrowly tailored health, safety, fire, building, sanitation, traffic, waste, pollution, noise, tax, and state/federal-compliance rules. Private deed restrictions, leases, and HOA or common-interest restrictions can also remain enforceable.
For unincorporated county zoning, Missouri section 64.008 also limits certain county zoning restrictions on home-based work. This means an older local home-occupation handout should not be read by itself. First determine whether the business falls within the state-protected category. If it creates impacts outside that safe harbor, then use the current County or municipal zoning process for the exact address.
Commercial occupancy and construction
Do not assume that an existing storefront is approved for your new use. A change of tenant or activity can trigger occupancy, zoning, building, fire, or trade-permit review. Clayton, for example, requires commercial occupancy approval before its business-license application, and Florissant requires zoning and commercial-occupancy review before a business license when one applies.
For unincorporated County locations, start with County Planning and Transportation/Public Works. Inside a municipality, begin with the municipality and ask whether any County electrical, mechanical, plumbing, fire, health, or other technical review also applies.
Food, mobile food, temporary food, catering, and cottage food
Restaurants, caterers, mobile food operators, and temporary food vendors should use the County Public Health food-permit routes and also check the municipality for local business, zoning, vending, event, or occupancy rules. A mobile food vendor in unincorporated County territory may also need the separate County street-vendor license described above.
Home food businesses are not all treated as restaurants. Missouri section 196.298 creates a cottage-food framework for specified foods produced in a home and sold directly to consumers. Qualifying cottage-food production is not treated as a food-service establishment for local-health regulation, but the statute has product, labeling, and sales conditions. If your food does not fit the cottage-food law, use the normal health-permit route.
Fire, signs, contractors, rentals, alcohol, and other regulated work
Fire authority can vary by address in St. Louis County, including municipalities and fire-protection districts. Signs may require zoning or building approval. Contractors and trades may face County or municipal credential and permit rules. Alcohol sales require Missouri and local approvals.
Short-term rentals also need an address-specific check. A rental inside a municipality may face municipal zoning, occupancy, registration, or business rules, while an unincorporated address starts with the County land-use and property requirements that apply to that parcel. Do not treat a state entity filing or ordinary lease as proof that short-term rental use is allowed.
For any regulated activity, identify the exact business type and address rather than assuming a general business license covers it.
What different business types should verify
| Business type | High-priority checks |
|---|---|
| Retail shop | Municipal business license, occupancy/zoning, County Assessor registration and merchant license, Missouri sales-tax registration, signs, and any product-specific permits. |
| Service office or freelancer | Municipal license if required, occupancy or home-business status, County Assessor registration, fictitious name if used, entity/tax steps, and any professional license. |
| Home-based business | First test the Missouri no-impact home-business protections; then check any legally permitted zoning, health, safety, parking, lease, HOA, and activity-specific rules. |
| Restaurant or caterer | Local business license, zoning/occupancy, County Public Health food permit and plan-review path, state tax registration, fire/building review, and alcohol licensing if applicable. |
| Food truck or motor-vehicle street vendor | County Public Health approval, County street-vendor license when operating in covered unincorporated territory, plus municipal vending/business rules where operating inside a city. |
| Contractor or trade business | Local business license if required, County/municipal trade or contractor credential, permits for each project, state registration/tax steps, and professional licensing when applicable. |
| Short-term rental | Municipal or unincorporated zoning/use rules, occupancy and safety requirements, any local registration or business rule, state tax/entity steps, and the rules for the exact property. |
| Online seller | Home-business or occupancy rules for the physical location, County Assessor registration, merchant license if retail/wholesale applies, Missouri sales-tax rules, DBA/entity filings, and any product-specific regulation. |
| Property-owning LLC | Normal entity, tax, zoning, rental, and local rules, plus the new section 347.048 affidavit only if the St. Louis County property meets both statutory ordinance-violation conditions. |
Common mistakes to avoid
- Confusing the City of St. Louis with St. Louis County. They are separate governments.
- Assuming a postal city controls the property. Confirm the municipal boundary for the exact address.
- Treating the County merchant license as a universal business license. It is tied to merchant/manufacturer rules, while municipalities and other County offices handle different layers.
- Calling a DBA a license. Missouri fictitious-name registration is a name filing, not permission to operate.
- Using an old home-occupation handout without checking state law. Missouri’s 2022 home-business protections materially limit local prior-approval rules for qualifying businesses.
- Signing a lease before confirming use and occupancy. Zoning, change-of-use, inspections, signs, and fire requirements can affect the location.
- Assuming a food permit covers local licensing. Health, business-license, zoning, vending, and tax requirements are separate layers.
- Ignoring employer steps after payroll starts. Withholding, unemployment, new-hire reporting, and federal employment-tax duties are different obligations.
What to ask before paying for or filing anything
Address and local license
“I plan to operate a [business type] at [street address]. Is this address inside your municipality or in unincorporated St. Louis County? What local business license, zoning approval, occupancy approval, and sign or fire review apply before I open?”
Home business
“I will run a [business type] from my home with [customers/employees/deliveries/signage/storage]. Does it qualify as a no-impact home-based business under Missouri section 71.990? If not, what specific zoning or safety rule applies to these facts?”
Food or mobile vending
“I will operate a [restaurant/catering/food truck/temporary food/cottage-food] business at or around [location]. Which Public Health permit applies, and is there a separate municipal or County vendor/business license for where I will sell?”
Ask the agency to name the exact permit or license and point you to the current application. That helps avoid paying for the wrong filing.
Official sources
- St. Louis County Geospatial Data Center — address and boundary research.
- St. Louis County Assessor business registration and merchant/manufacturer application.
- St. Louis County Revenue Licensing, Licensing FAQs, and the street-vendor application.
- St. Louis County Planning and zoning verification.
- St. Louis County Commercial Building, permit applications, and the County permits and code enforcement directory.
- St. Louis County Food and Restaurants and food permit applications.
- Missouri section 347.048 — certain LLC-owned real property affidavits.
- Missouri section 71.990 and section 64.008 — home-business protections and county zoning limits.
- Missouri Secretary of State Corporations Division and fictitious-name FAQ.
- Missouri Department of Revenue Business Tax Registration.
- Missouri UInteract employer registration and Missouri New Hire Reporting.
- Missouri Division of Professional Registration.
- IRS EIN service.
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FAQ
Does every business in St. Louis County need the same county business license?
No. There is not one universal county license that replaces municipal and activity-specific requirements. The County Assessor has business personal property registration and merchant/manufacturer licensing, while cities, County departments, and state agencies handle other approvals.
How do I know whether my business is in a city or unincorporated St. Louis County?
Use St. Louis County GIS, property lookup, and municipal-boundary tools for the street address, then confirm with the relevant city or County office before applying. Do not rely only on the mailing-city name.
Is the City of St. Louis part of St. Louis County?
No. The City of St. Louis is an independent city and a separate governmental entity. If the business is inside the City of St. Louis, use the City’s license and permit process.
Is a Missouri fictitious name the same as a business license?
No. A fictitious name, often called a DBA, is a Missouri Secretary of State name filing. It does not replace a local business license, zoning approval, tax account, food permit, or professional license.
Do home businesses always need a home occupation permit?
No. Missouri section 71.990 bars political subdivisions from requiring a local permit, license, variance, registration, or other prior approval for a qualifying no-impact home-based business. Businesses outside that protected category can still face legally permitted zoning, health, safety, building, traffic, tax, and activity-specific rules.
Does every St. Louis County LLC that owns rental property have to file the new county-clerk affidavit?
No. The county provision in Missouri section 347.048 applies only when the property has more than two ordinance violations at the same location and an attempt to resolve the violation with the registered agent was unsuccessful. It took effect August 28, 2026.
What should I check before I sign a commercial lease?
Confirm the jurisdiction, zoning/use approval, occupancy requirements, building or fire work, signs, parking or site limits, local business license, and any health or industry permit. A lease does not prove the government will approve your intended use.
Update note
Last updated: October 5, 2026
Next review: January 3, 2027
This refresh rechecked St. Louis County versus municipal jurisdiction, Assessor registration and merchant/manufacturer licensing, County activity licensing, zoning and occupancy, food permits, Missouri fictitious-name and tax filings, employer steps, and home-business protections. It also adds the August 28, 2026 St. Louis County LLC-property affidavit change in Missouri section 347.048 and corrects older home-business guidance to reflect Missouri’s 2022 statutory protections.
Informational disclaimer
This guide is for general information only. Business license, tax, zoning, health, building, and permit rules can change and depend on the exact address and activity. Confirm current requirements with the responsible government agency before paying a fee, signing a lease, opening to the public, or filing forms.