36,437 people (2024 Census estimate, −3.2% since 2020)
573 square miles of land · 64 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.
15 active community water systems list Marion County in the area they serve, reporting 42,624 people served in all (a system that crosses county lines counts its whole population).
| CENTRALIA surface water · local government · IL1214220 | 12,182 served |
| SALEM surface water · local government · IL1210450 | 7,905 served |
| RACCOON WATER COMPANY buys surface water · private · IL1215100 | 7,080 served |
| NORTH EAST MARION COUNTY WATER CMPNY buys surface water · private · IL1210030 | 3,220 served |
| FMC WATER COMPANY buys surface water · private · IL1210020 | 2,945 served |
| ODIN buys surface water · local government · IL1210350 | 2,543 served |
| SANDOVAL buys surface water · local government · IL1210500 | 1,422 served |
| WALNUT HILL buys surface water · local government · IL1210600 | 1,180 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 119 people were held in Marion County's jail, in Vera's latest figure (2019), or 515 per 100,000 residents ages 15–64. In 2014 it was about 100.
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.
13 school districts have their office in Marion County. School taxes are usually the largest part of a property tax bill.
Spent $23 million — $18 million to run schools, about $16,500 per student, plus $4.1 million on buildings and equipment. Money in: $4.7 million local (mostly property tax), $15.7 million state, $5.8 million federal. Long-term debt: $5.1 million.
Spent $17.5 million — $11.3 million to run schools, about $12,128 per student, plus $5.1 million on buildings and equipment. Money in: $3.5 million local (mostly property tax), $8.3 million state, $4.8 million federal. Long-term debt: $6.9 million.
Spent $19.9 million — $18.2 million to run schools, about $21,043 per student, plus $954,000 on buildings and equipment. Money in: $8.1 million local (mostly property tax), $13.2 million state, $2.4 million federal. Long-term debt: $5.6 million.
Spent $16.6 million — $8.5 million to run schools, about $11,654 per student, plus $7.2 million on buildings and equipment. Money in: $5.6 million local (mostly property tax), $5.9 million state, $912,000 federal. Long-term debt: $10.8 million.
Spent $10.7 million — $9 million to run schools, about $14,280 per student, plus $952,000 on buildings and equipment. Money in: $4 million local (mostly property tax), $6.4 million state, $1.9 million federal. Long-term debt: $4 million.
Spent $7.7 million — $6.6 million to run schools, about $15,629 per student, plus $832,000 on buildings and equipment. Money in: $1.7 million local (mostly property tax), $5.6 million state, $2.2 million federal. Long-term debt: $793,000.
Spent $4.4 million — $4.1 million to run schools, about $12,632 per student, plus $90,000 on buildings and equipment. Money in: $772,000 local (mostly property tax), $3.6 million state, $1.2 million federal. Long-term debt: $236,000.
Spent $6.8 million — $4 million to run schools, about $15,766 per student, plus $2.5 million on buildings and equipment. Money in: $1.1 million local (mostly property tax), $3 million state, $1.7 million federal. Long-term debt: $1.8 million.
And 5 more.
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: Relatively Low compared with other U.S. counties. FEMA estimates natural hazards cost Marion County about $30.9 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very High; social vulnerability: Relatively High.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
294 bridges in Marion County: 182 in good condition, 90 fair, and 22 poor (7.5%). “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.
| FAI-57 NB over CROOKED CREEK · built 1968 | 9,650 vehicles a day |
| FAI-57 SB over CROOKED CREEK · built 1968 | 9,650 vehicles a day |
| I-57 SB over CSXRR · built 1968 | 9,650 vehicles a day |
| FAI-57 SB over US-50 · built 1968 | 8,350 vehicles a day |
| IL 161 - FAP 805 over FAI-57 · built 1968 | 3,900 vehicles a day |
| OLD US 51 (FAS 179 over CROOKED CREEK · built 1954 | 1,450 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $19.3 million of work in Marion County in fiscal 2025, about $510 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 Illinois 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 Marion 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 Marion County built: brayden.ozark@gmail.com.
More of Illinois: the state government and every county in Illinois.
Nearby counties: Jefferson County (24 mi) · Clay County (25 mi) · Fayette County (25 mi) · Clinton County (27 mi) · Wayne County (30 mi) · Bond County (32 mi).