Buying in St. Louis County, Missouri

St. Louis County at a glance

St. Louis County is one of 115 counties and county-equivalents in Missouri. Its county seat is Clayton. With a 2024 Census Bureau population estimate of 992,929, it is the most populous county in Missouri. In the FBI's 2024 reported-crime file, agencies here reported 22,140 offenses — 22.3 per 1,000 residents; the breakdown is below.

Records to check before you buy in St. Louis County

• Property record card — the St. Louis County assessor / appraisal office. Pull the parcel's assessed-value history, exemption status, and last sale. This is the file your future tax bill is calculated from, and it shows whether the current owner is enjoying exemptions you will not inherit. County government sits in Clayton — start there for office locations and the parcel search.
• Deeds & liens — the St. Louis County recorder / land-records office. Read the deed chain, open liens, easements, and plat maps — the file a listing never mentions.
• Official flood determination. Check the exact parcel on FEMA's National Flood Hazard Layer — not the listing site's licensed model. Zone boundaries cut through streets; the house next door can be in a different zone. St. Louis County is the primary county for 43 ZIP codes in the Census Bureau's ZIP-to-county crosswalk — and zone lines ignore every one of them.
• The county's reported-crime record. In the FBI's 2024 file, agencies in St. Louis County reported 22,140 offenses — 22.3 per 1,000 residents; the largest single category was larceny-theft (12,892). The crime section below sets that beside the Missouri county median.
• Registry check. Run the address through Missouri Sex Offender Registry (Missouri State Highway Patrol, Criminal Justice Information Services Division) and note the counts within a mile — then check again the week you close.
• Permits & code history — the St. Louis building department. Open permits, expired permits, and code cases tell you whether the renovation in the photos was ever inspected. County permitting is run out of Clayton.
• School assignment — the district office, not the listing. Only the district's own boundary lookup confirms which school an address is actually zoned for.

County list, land area and population: U.S. Census Bureau (population: 2024 PEP estimate). County seat and official website: Wikidata (CC0), checked 2026-11-04. Flood determinations: FEMA. Registry: Missouri.

Reported crime in St. Louis County — FBI 2024

Agencies in St. Louis County reported 22,140 offenses to the FBI in 2024 — 3,900 violent and 18,240 property offenses. That works out to a reported-crime rate of 22.3 per 1,000 residents (violent 392.8, property 1837.0 per 100,000).

Inside Missouri, the median county in the same file recorded a violent-crime rate of 210 per 100,000 and a property-crime rate of 728 per 100,000 (medians computed from the FBI 2024 county file across 115 counties).

The largest reported categories were larceny-theft (12,892), motor vehicle theft (3,476) and aggravated assault (3,109).

Coverage: 60 of 60 law-enforcement agencies assigned to this county reported at least one month of 2024 offense data to the FBI; 52 reported all 12 months. Counts are reported offenses only (FBI Return A / Arson master files), assigned whole to each agency's primary county; they are not adjusted for non-reporting agencies.

These are offenses reported to law enforcement — not convictions, and not a verdict on any street or address. A CurbFacts report pairs this county record with the ZIP-level picture for the specific address you are buying.

Source: FBI Crime Data Explorer, UCR Return A + Arson master files, data year 2024 (pulled 2026-11-04).

The Missouri rules that apply in St. Louis County

Traps researched for Missouri buyers: Odd-year reassessment can jump with no homestead cap; Meth-production disclosure is a specific statutory duty.

Read the full Missouri guide — disclosure standard, tax math, registry and flood

More Missouri counties

All Missouri counties · Missouri buyer guide