42,648 people (2024 Census estimate, +0.3% since 2020)
462 square miles of land · 92 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.
9 active community water systems list Mercer County in the area they serve, reporting 22,904 people served in all (a system that crosses county lines counts its whole population).
| CELINA, CITY OF surface water · local government · OH5400011 | 11,682 served |
| COLDWATER VILLAGE groundwater · local government · OH5400112 | 4,774 served |
| ST HENRY VILLAGE groundwater · local government · OH5401312 | 2,596 served |
| FT RECOVERY VILLAGE groundwater · local government · OH5400212 | 1,501 served |
| ROCKFORD VILLAGE groundwater · local government · OH5401112 | 1,120 served |
| MENDON VILLAGE groundwater · local government · OH5400612 | 628 served |
| CHICKASAW VILLAGE groundwater · local government · OH5402212 | 358 served |
| SAINT CHARLES CENTER groundwater · private · OH5401212 | 142 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 67 people were held in Mercer County's jail, in Vera's latest figure (2023), or 270 per 100,000 residents ages 15–64. In 2018 it was about 78.
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.
6 school districts have their office in Mercer County. School taxes are usually the largest part of a property tax bill.
Spent $49.4 million — $36.5 million to run schools, about $12,449 per student, plus $9.4 million on buildings and equipment. Money in: $27 million local (mostly property tax), $19.8 million state, $5.8 million federal. Long-term debt: $89.1 million.
Spent $18.7 million — $17.3 million to run schools, about $12,278 per student, plus $970,000 on buildings and equipment. Money in: $8.4 million local (mostly property tax), $8.7 million state, $910,000 federal. Long-term debt: $5.7 million.
Spent $11.9 million — $11.1 million to run schools, about $10,914 per student, plus $643,000 on buildings and equipment. Money in: $5.1 million local (mostly property tax), $6.1 million state, $713,000 federal. Long-term debt: $80,000.
Spent $13.4 million — $12.2 million to run schools, about $12,134 per student, plus $1.1 million on buildings and equipment. Money in: $6.9 million local (mostly property tax), $6.8 million state, $827,000 federal. Long-term debt: $2.2 million.
Spent $14.6 million — $13.2 million to run schools, about $13,549 per student, plus $986,000 on buildings and equipment. Money in: $7.4 million local (mostly property tax), $7.5 million state, $1.9 million federal. Long-term debt: $4.3 million.
Spent $11.9 million — $10.4 million to run schools, about $11,106 per student, plus $1.4 million on buildings and equipment. Money in: $5.1 million local (mostly property tax), $6.5 million state, $988,000 federal. Long-term debt: $100,000.
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 Mercer County about $18 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.
327 bridges in Mercer County: 149 in good condition, 173 fair, and 5 poor (1.5%). “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.
| SIEGRIST JUTTE RD over WABASH RIVER · built 1987 | 1,194 vehicles a day |
| SHARPSBURG ROAD over BRANCH OF WABASH RIVER · built 1965 | 723 vehicles a day |
| ROCKFORD WEST ROAD over BIG BLACKCREEK · built 1985 | 272 vehicles a day |
| HUWER ROAD over BR OF MILE CREEK · built 1993 | 235 vehicles a day |
| ERASTUS DURBIN RD over BIG RUN · built 1911 | 172 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $2.5 million of work in Mercer County in fiscal 2025, about $59 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 Ohio 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 Mercer 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 Mercer County built: brayden.ozark@gmail.com.
More of Ohio: the state government and every county in Ohio.
Nearby counties: Jay County, IN (21 mi) · Auglaize County (21 mi) · Adams County, IN (22 mi) · Van Wert County (22 mi) · Shelby County (26 mi) · Darke County (28 mi).