71,721 people (2024 Census estimate, +13.7% since 2020)
432 square miles of land · 166 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.
4 active community water systems list Union County in the area they serve, reporting 28,663 people served in all (a system that crosses county lines counts its whole population).
| MARYSVILLE CITY PWS surface water · local government · OH8000314 | 25,571 served |
| RICHWOOD VILLAGE PWS groundwater · local government · OH8000412 | 2,200 served |
| MILFORD CENTER VILLAGE PWS groundwater · local government · OH8000212 | 792 served |
| NEW DOVER ESTATES groundwater · private · OH8000012 | 100 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 66 people were held in Union County's jail, in Vera's latest figure (2023), or 142 per 100,000 residents ages 15–64. In 2018 it was about 80.
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.
3 school districts have their office in Union County. School taxes are usually the largest part of a property tax bill.
Spent $74.9 million — $70.2 million to run schools, about $12,642 per student, plus $1.5 million on buildings and equipment. Money in: $44.8 million local (mostly property tax), $28.4 million state, $7 million federal. Long-term debt: $45 million.
Spent $22.4 million — $20.8 million to run schools, about $14,721 per student, plus $1.4 million on buildings and equipment. Money in: $11.4 million local (mostly property tax), $10.3 million state, $1.4 million federal. Long-term debt: $3.4 million.
Spent $16.1 million — $14.7 million to run schools, about $13,716 per student, plus $958,000 on buildings and equipment. Money in: $13.1 million local (mostly property tax), $4.2 million state, $843,000 federal. Long-term debt: $7.4 million.
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 Union County about $19 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.
221 bridges in Union County: 149 in good condition, 64 fair, and 8 poor (3.6%). “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 36 over MILL CREEK · built 1950 | 18,155 vehicles a day |
| USR 42 over ROBINSON RUN · built 1982 | 8,156 vehicles a day |
| USR 36 over TREACLE CREEK · built 1966 | 4,977 vehicles a day |
| SR 161 over LITTLE DARBY CREEK · built 1963 | 1,461 vehicles a day |
| SR 37 over BOKES CREEK · built 1982 | 836 vehicles a day |
| CR 36 (BG Rd) over US 33 · built 1968 | 562 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $35.7 million of work in Union County in fiscal 2025, about $569 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 Union 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 Union County built: brayden.ozark@gmail.com.
More of Ohio: the state government and every county in Ohio.
Nearby counties: Delaware County (19 mi) · Logan County (22 mi) · Marion County (23 mi) · Champaign County (24 mi) · Madison County (28 mi) · Franklin County (29 mi).