53,835 people (2024 Census estimate, +2.5% since 2020)
418 square miles of land · 129 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.
20 active community water systems list Grundy County in the area they serve, reporting 42,957 people served in all (a system that crosses county lines counts its whole population).
| MORRIS groundwater · local government · IL0630600 | 14,775 served |
| MINOOKA groundwater · local government · IL0630550 | 12,800 served |
| COAL CITY groundwater · local government · IL0630200 | 5,845 served |
| DIAMOND groundwater · local government · IL0630250 | 2,508 served |
| GARDNER groundwater · local government · IL0630400 | 1,361 served |
| MAZON groundwater · local government · IL0630500 | 994 served |
| SHADY OAKS MHP groundwater · private · IL0635225 | 912 served |
| BRACEVILLE groundwater · local government · IL0630050 | 800 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 33 people were held in Grundy County's jail, in Vera's latest figure (2019), or 96 per 100,000 residents ages 15–64. In 2014 it was about 41.
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.
12 school districts have their office in Grundy County. School taxes are usually the largest part of a property tax bill.
Spent $71.7 million — $62.1 million to run schools, about $13,808 per student, plus $1.6 million on buildings and equipment. Money in: $45.4 million local (mostly property tax), $28.8 million state, $4.5 million federal. Long-term debt: $49.1 million.
Spent $66.7 million — $53.7 million to run schools, about $18,338 per student, plus $7.4 million on buildings and equipment. Money in: $54.6 million local (mostly property tax), $20.7 million state, $1.3 million federal. Long-term debt: $43.1 million.
Spent $35.1 million — $32.6 million to run schools, about $15,447 per student, plus $598,000 on buildings and equipment. Money in: $29.6 million local (mostly property tax), $9.4 million state, $1.7 million federal. Long-term debt: $25.6 million.
Spent $18.4 million — $13.7 million to run schools, about $12,715 per student, plus $1.8 million on buildings and equipment. Money in: $10.8 million local (mostly property tax), $7.7 million state, $2.2 million federal. Long-term debt: $20 million.
Spent $17.5 million — $12.7 million to run schools, about $13,388 per student, plus $864,000 on buildings and equipment. Money in: $13.9 million local (mostly property tax), $5.3 million state, $992,000 federal. Long-term debt: $6.1 million.
Spent $12.7 million — $10.2 million to run schools, about $13,150 per student, plus $864,000 on buildings and equipment. Money in: $11.3 million local (mostly property tax), $2.5 million state, $856,000 federal. Long-term debt: $17.3 million.
Spent $5.7 million — $4.5 million to run schools, about $14,261 per student, plus $369,000 on buildings and equipment. Money in: $4.7 million local (mostly property tax), $1.6 million state, $277,000 federal. Long-term debt: $3.7 million.
Spent $3.7 million — $2.6 million to run schools, about $17,561 per student, plus $673,000 on buildings and equipment. Money in: $1.4 million local (mostly property tax), $1.9 million state, $392,000 federal. Long-term debt: $185,000.
And 4 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 Grundy County about $50.1 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very High; social vulnerability: Very Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
268 bridges in Grundy County: 97 in good condition, 95 fair, and 76 poor (28.4%). “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.
| ILL 47 over ARMSTRONG & B & O RR · built 1978 | 21,000 vehicles a day |
| ILL 47 over BUCHANAN ST · built 1978 | 21,000 vehicles a day |
| US 6 over AUX SABLE CR · built 1969 | 7,050 vehicles a day |
| US 6 over CSX Railroad · built 1974 | 7,050 vehicles a day |
| BROADWAY ST N/MS60 over CLAYPOOL DRAIN DITCH · built 1982 | 1,850 vehicles a day |
| Ashton Rd / TR 106 over FAI 80 · built 1958 | 1,650 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $23 million of work in Grundy County in fiscal 2025, about $437 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 Grundy 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 Grundy County built: brayden.ozark@gmail.com.
More of Illinois: the state government and every county in Illinois.
Nearby counties: Kendall County (20 mi) · Will County (24 mi) · LaSalle County (25 mi) · Livingston County (29 mi) · Kankakee County (30 mi) · DuPage County (42 mi).