Overview
St. Louis County is home to 996,618 people (Census ACS 5-Year, 2023), making it the largest county in Missouri by population and larger than 98% of all U.S. counties. It sits just west of the independent city of St. Louis, forming the core of the greater metro area.
The county's median household income of $81,340 (Census ACS 5-Year, 2023) ranks higher than 85% of U.S. counties and 95% of Missouri counties. Nearly half of adults hold a bachelor's degree or higher. Per capita income reaches $51,085 (Census ACS 5-Year, 2023), above 95% of counties nationally.
Those top-line numbers put St. Louis County in a distinct economic tier. But the profile gets more complicated below the surface: a 9.4% poverty rate, a 6.9% vacancy rate, and 34 federal disaster declarations since 2006 add texture that the income figures alone don't capture.
Demographics
The median age is 40.2 years (Census ACS 5-Year, 2023), roughly in the middle of the pack nationally.
Education levels stand out. Some 46.9% of residents 25 and older hold at least a bachelor's degree (Census ACS 5-Year, 2023), a rate higher than 96% of U.S. counties. Within Missouri, only one or two counties exceed it. That concentration of educational attainment shapes the labor market, housing demand, and tax base in measurable ways.
The county's racial composition: 62.0% white, 24.1% Black, 4.7% Asian, 0.1% Native American, and 3.7% Hispanic or Latino (Census ACS 5-Year, 2023). The Black population share ranks higher than 87% of U.S. counties and 97% of Missouri counties. The Asian population share, at 4.7%, exceeds 94% of counties nationally.
St. Louis County is, by these measures, one of the more racially diverse counties in Missouri and considerably more diverse than most counties in the country.
Education
Per-pupil spending in St. Louis County is $17,434 (Education Data Portal, 2020), about 16% above the national average of roughly $15,000. That figure ranks higher than 73% of U.S. counties and 98% of Missouri counties.
The student-teacher ratio sits at 11.8 to 1 (Education Data Portal, 2021), well below the national average of about 15.5 to 1. Smaller class sizes don't guarantee outcomes, but the gap is significant. Total enrollment across the county's school districts is 134,855 students (Education Data Portal, 2021).
The graduation rate is 87.1% (Education Data Portal, 2019), nearly identical to the national average. For a county that spends well above average per student and maintains smaller classes, a middling graduation rate raises questions about where the resources go and who benefits from them.
Economy & Employment
The labor force numbers 533,119 people, with 515,433 employed and 17,686 unemployed as of early 2025 (BLS LAUS, 2025). The unemployment rate of 3.3% falls below the national average, ranking lower than roughly 68% of U.S. counties. Employment is broad and relatively stable.
Median household income of $81,340 (Census ACS 5-Year, 2023) sits well above the national median of about $75,149. Per capita income of $51,085 (Census ACS 5-Year, 2023) tells a similar story.
The poverty rate is 9.4% (Census ACS 5-Year, 2023), lower than about 78% of U.S. counties. In a county with high aggregate income, that rate still means roughly 94,000 residents live below the poverty line. Average adjusted gross income per tax return was $120,814 (IRS Statistics of Income, 2021), which ranks above 96% of U.S. counties. The distance between that average and the poverty rate points to meaningful income dispersion within the county.
The mean commute is 19.5 minutes (Census ACS 5-Year, 2023), shorter than about 72% of U.S. counties. Most workers aren't traveling far.
Housing & Cost of Living
The median home value is $260,700 (Census ACS 5-Year, 2023), higher than 78% of U.S. counties and 96% of Missouri counties. Median gross rent is $1,164 per month (Census ACS 5-Year, 2023), above 84% of counties nationally.
The county has 445,472 total housing units, with 30,733 sitting vacant (Census ACS 5-Year, 2023). That's a vacancy rate of 6.9%, which actually falls in the bottom 12% nationally. Most U.S. counties have higher vacancy rates. Low vacancy in a high-cost market means limited slack for renters and buyers looking for options.
Fair market rent data from HUD (2026) was collected for this county but bedroom-level breakdowns are not available in the current dataset.
The ratio of home value to household income (roughly 3.2 to 1) remains within conventional affordability thresholds. But rents at $1,164 consume a larger share of income for households below the median. For a household earning $40,000, that rent represents more than a third of gross income.
Health & Wellness
St. Louis County's health indicators paint a mixed picture when compared nationally and a favorable one within Missouri.
The obesity rate is 31.5% (CDC PLACES, 2023), lower than roughly 90% of U.S. counties. Within Missouri, no county reports a lower rate. Depression affects 23.6% of adults (CDC PLACES, 2023). Poor mental health days are reported by 17.1% of adults, a rate better than about 79% of U.S. counties. Poor physical health days affect 11.7%, better than 88% of counties.
High blood pressure prevalence stands at 32.5% (CDC PLACES, 2023), near the national midpoint. Diabetes prevalence is 9.6%, lower than 75% of counties.
On the preventive care side, 77.3% of adults report an annual checkup and 84.8% have had cholesterol screening (CDC PLACES, 2023). Both figures rank in the upper quarter nationally.
The uninsured rate is 7.3% (CDC PLACES, 2023), lower than 92% of U.S. counties and the second-lowest tier in Missouri. High insurance coverage and strong preventive care usage likely contribute to the county's better-than-average physical health outcomes.
Climate & Natural Disasters
Thirty-four federal disaster declarations since 1973 puts St. Louis County above 92% of U.S. counties (FEMA OpenFEMA, 2026). The county sits where multiple severe weather patterns converge, and the record shows it.
Average temperature runs 57.5°F annually, with typical highs of 67.9°F and lows of 47.2°F (NOAA Climate Data Online, 2025). Annual precipitation is 39.8 inches. The county averages 25.3 inches of snow per year, and winter storms have generated federal emergency declarations more than once.
Floods have driven the disaster history harder than anything else. Federal flood declarations arrived in 1982, 1986, 1993 (twice in one year), 2000, 2011, 2016 (twice), 2017, and 2022. Nine flood declarations across four decades isn't a run of bad luck. It reflects persistent exposure along river corridors that recur regardless of what's built nearby.
Severe storms round out the picture. More than a dozen severe storm declarations appear in the FEMA record since 1973, with three in 2008 alone. Ice storms have earned their own category: separate federal emergency declarations in January 2007, December 2007, and January 2009 show that winter weather can be genuinely disruptive here, not just inconvenient.
The two most recent declarations, both severe storms in May and June 2025 (FEMA, 2025), fit the established pattern.
For anyone evaluating long-term risk, the flood history matters most. Repeated declarations in the same general timeframes point to chronic exposure in parts of the county, and climate trends don't favor that number trending down.
Financial Profile
Residents filed 495,050 federal tax returns reporting total adjusted gross income of $59.8 billion and total income of $60.4 billion (IRS Statistics of Income, 2021). Average AGI per return was $120,814. Average total income per return was $122,034. Both figures rank above 96% of U.S. counties and above 99% of Missouri counties.
The county has 199 FDIC-insured bank branches holding $27.9 billion in total deposits (FDIC Summary of Deposits, 2023). Branch count ranks above 97% of U.S. counties. Deposit totals rank similarly. Banking access is extensive.
Social Security beneficiaries total 216,865 (SSA OASDI, 2024), the highest count in Missouri and above 99% of U.S. counties. That's roughly 22% of the total population receiving OASDI benefits, consistent with the county's median age of 40.2 and its large retired population base.
Key Comparisons
St. Louis County consistently ranks in the top tier of Missouri counties across income, education, and health metrics.
Compared to the national median household income of approximately $75,149, the county's $81,340 (Census ACS 5-Year, 2023) is about 8% higher. Per capita income of $51,085 exceeds the national figure by a wider margin.
The bachelor's degree attainment rate of 46.9% roughly doubles the national rate of about 23%. This is one of the county's most distinctive metrics.
The poverty rate of 9.4% runs below the national rate of about 12.4%. Unemployment at 3.3% (BLS LAUS, 2025) is below the national average. Home values and rents track above national medians but not at the extremes seen in coastal metro counties.
Health outcomes rank better than most U.S. counties, particularly for obesity (lower than 90% of counties), uninsured rate (lower than 92%), and poor physical health (better than 88%). Within Missouri, St. Louis County ranks at or near the top for nearly every health metric.
The gap between the county's educational investment ($17,434 per pupil) and its graduation rate (87.1%, essentially average) is the most notable disconnect in the data. High spending and small class sizes haven't translated into above-average completion rates.
Disaster exposure is another area of concern. With 34 federal declarations, the county faces recurring severe weather costs that most U.S. counties don't.
Data Sources
- U.S. Census Bureau, American Community Survey 5-Year Estimates, 2023
- Bureau of Labor Statistics, Local Area Unemployment Statistics, 2025
- CDC PLACES, 2023
- HUD Fair Market Rents, 2026
- FEMA OpenFEMA Disaster Declarations, 2026
- IRS Statistics of Income, 2021
- FDIC Summary of Deposits, 2023
- NOAA Climate Data Online, 2025
- Social Security Administration OASDI Beneficiaries, 2024
- Education Data Portal (finance 2020, directory 2021, graduation rate 2019)