3,452 people (2024 Census estimate, −1.7% since 2020)
454 square miles of land · 8 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.
3 active community water systems list Mercer County in the area they serve, reporting 4,801 people served in all (a system that crosses county lines counts its whole population).
| MERCER COUNTY PWSD 1 buys surface water · local government · MO2024382 | 3,200 served |
| PRINCETON PWS groundwater · local government · MO2010664 | 1,283 served |
| MERCER PWS buys groundwater · local government · MO2010515 | 318 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 4 people were held in Mercer County's jail, in Vera's latest figure (2019), or 191 per 100,000 residents ages 15–64. In 2014 it was about 2.
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.
2 school districts have their office in Mercer County. School taxes are usually the largest part of a property tax bill.
Spent $6 million — $5.4 million to run schools, about $14,709 per student, plus $457,000 on buildings and equipment. Money in: $3.9 million local (mostly property tax), $2.2 million state, $1.6 million federal. Long-term debt: $5.2 million.
Spent $3.3 million — $2.8 million to run schools, about $19,441 per student, plus $152,000 on buildings and equipment. Money in: $1.5 million local (mostly property tax), $1.2 million state, $923,000 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 Mercer County about $4 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very Low; social vulnerability: Relatively High.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
135 bridges in Mercer County: 62 in good condition, 50 fair, and 23 poor (17.0%). “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.
| US 136 E over GRAND RVR OVRFL · built 1971 | 1,917 vehicles a day |
| RT E E over W MEDICINE CK · built 1971 | 439 vehicles a day |
| RT E E over W HONEY CR · built 1932 | 309 vehicles a day |
| BRANT ST E over UP RR · built 1900 | 218 vehicles a day |
| RT D E over WEST MUDDY CR · built 1935 | 121 vehicles a day |
| RT JJ E over HONEY CR · built 1957 | 67 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $14.6 million of work in Mercer County in fiscal 2025, about $4,132 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 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 Missouri: the state government and every county in Missouri.
Nearby counties: Grundy County (21 mi) · Harrison County (23 mi) · Decatur County, IA (25 mi) · Wayne County, IA (25 mi) · Sullivan County (28 mi) · Putnam County (29 mi).