9,848 people (2024 Census estimate, +5.4% since 2020)
675 square miles of land · 15 people per square mile
“Highest” and “lowest” are just order, not grades: a high rank for poverty or hazard losses means more of it. Each figure's source is in its section below.
6 active community water systems list St. Clair County in the area they serve, reporting 5,512 people served in all (a system that crosses county lines counts its whole population).
| HARRY S TRUMAN PWSD 2 surface water · local government · MO1024247 | 2,700 served |
| APPLETON CITY PWS buys surface water · local government · MO5010020 | 1,050 served |
| OSCEOLA PWS groundwater · local government · MO5010612 | 947 served |
| LOWRY CITY PWS groundwater · local government · MO5010480 | 640 served |
| COLLINS PWS groundwater · local government · MO5010884 | 125 served |
| TWIN OAKS HARBOR groundwater · private · MO5240546 | 50 served |
Source: U.S. EPA Safe Drinking Water Information System (SDWIS), active community systems, . Look up any system's violations and test results with EPA's search using its ID.
About 136 people were held in St. Clair County's jail, in Vera's latest figure (2019), or 2,604 per 100,000 residents ages 15–64. In 2014 it was about 136.
Source: Vera Institute of Justice, Incarceration Trends (built from federal Bureau of Justice Statistics jail surveys). Counties without their own jail, or that share one, may show no figure.
4 school districts have their office in St. Clair County. School taxes are usually the largest part of a property tax bill.
Spent $7.3 million — $6.2 million to run schools, about $11,128 per student, plus $1.1 million on buildings and equipment. Money in: $2.5 million local (mostly property tax), $3.2 million state, $1.6 million federal.
Spent $10.5 million — $8.2 million to run schools, about $19,971 per student, plus $1.8 million on buildings and equipment. Money in: $7.5 million local (mostly property tax), $2.6 million state, $2.1 million federal. Long-term debt: $2.8 million.
Spent $4.8 million — $4.6 million to run schools, about $14,870 per student, plus $164,000 on buildings and equipment. Money in: $1.9 million local (mostly property tax), $1.9 million state, $965,000 federal.
Spent $1.2 million — $986,000 to run schools, about $18,962 per student, plus $32,000 on buildings and equipment. Money in: $389,000 local (mostly property tax), $589,000 state, $406,000 federal.
Source: U.S. Census Bureau, 2023 Annual Survey of School System Finances. Districts are listed by the county of their main office; some serve neighboring counties too.
Source: County Health Rankings & Roadmaps 2025 (University of Wisconsin Population Health Institute), which gathers federal data (CDC, Census, and others); measures cover different recent years. Blank lines aren't reported for small counties.
Overall risk: Very Low compared with other U.S. counties. FEMA estimates natural hazards cost St. Clair County about $6.1 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively Low; social vulnerability: Very High.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
139 bridges in St. Clair County: 36 in good condition, 76 fair, and 27 poor (19.4%). “Poor” means a main part — the deck, the beams, or the supports — is rated 4 or lower on the federal 0–9 scale. It doesn't mean unsafe to drive; unsafe bridges are closed.
| MO 13 N over OTTER CR · built 1963 | 8,984 vehicles a day |
| MO 13 N over BRUSH CR · built 1962 | 5,727 vehicles a day |
| MO 82 E over LIT CLEAR CR · built 1991 | 971 vehicles a day |
| MO 82 E over BEAR CR · built 1978 | 803 vehicles a day |
| RT C E over BIG MUDDY CR · built 1976 | 763 vehicles a day |
| RT B E over SALT CR · built 1976 | 450 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $2.8 million of work in St. Clair County in fiscal 2025, about $297 per resident — to the county, cities, schools, hospitals, nonprofits and others.
Source: USAspending.gov, grants by place of performance, fiscal 2025 (Oct. 2024 to Sept. 2025). Search it by county to see each award.
From Grants.gov: posted grants listing county governments as eligible, soonest deadline first; research-only and overseas programs left out; list updated 2026-10-13, refreshed weekly. 62 are open in all. Cities, towns, school districts and nonprofits have their own lists there.
Registration deadlines, early voting and polling places for Missouri are on the federal site vote.gov, which links to the state's official election office.
The budget, property tax rates, audits, local officials and offices for St. Clair County come from the county's own records, which we haven't gathered — not gathered, never hidden. See what a full county site looks like, or ask to have St. Clair County built: brayden.ozark@gmail.com.
More of Missouri: the state government and every county in Missouri.
Nearby counties: Cedar County (22 mi) · Henry County (24 mi) · Hickory County (26 mi) · Benton County (32 mi) · Vernon County (33 mi) · Bates County (34 mi).