111,950 people (2024 Census estimate, +2.7% since 2020)
407 square miles of land · 275 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.
16 active community water systems list Miami County in the area they serve, reporting 94,120 people served in all (a system that crosses county lines counts its whole population).
| NAWA groundwater · private · OH5553612 | 29,974 served |
| TROY CITY PWS groundwater · local government · OH5501612 | 26,305 served |
| PIQUA CITY PWS surface water · local government · OH5501211 | 20,354 served |
| WEST MILTON VILLAGE PWS buys groundwater · local government · OH5501711 | 4,890 served |
| MIAMI CO-CAMP TROY PWS buys groundwater · private · OH5502503 | 3,813 served |
| COVINGTON VILLAGE PWS groundwater · local government · OH5500112 | 2,718 served |
| MIAMI CO-N25A EXTENSION buys groundwater · private · OH5502303 | 2,367 served |
| PLEASANT HILL VILLAGE PWS groundwater · local government · OH5501312 | 1,226 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 154 people were held in Miami County's jail, in Vera's latest figure (2023), or 226 per 100,000 residents ages 15–64. In 2018 it was about 187.
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.
9 school districts have their office in Miami County. School taxes are usually the largest part of a property tax bill.
Spent $58.7 million — $54 million to run schools, about $13,266 per student, plus $2.8 million on buildings and equipment. Money in: $38.8 million local (mostly property tax), $19.4 million state, $6.7 million federal. Long-term debt: $9.9 million.
Spent $54 million — $46.6 million to run schools, about $14,778 per student, plus $5.6 million on buildings and equipment. Money in: $26.4 million local (mostly property tax), $21.4 million state, $7.1 million federal. Long-term debt: $29.9 million.
Spent $33.1 million — $31.6 million to run schools, about $13,287 per student, plus $1.2 million on buildings and equipment. Money in: $21.1 million local (mostly property tax), $10.7 million state, $2.3 million federal. Long-term debt: $5.8 million.
Spent $42.8 million — $18.6 million to run schools, about $9,966 per student, plus $23.5 million on buildings and equipment. Money in: $13.7 million local (mostly property tax), $9 million state, $1.5 million federal. Long-term debt: $47.6 million.
Spent $20.7 million — $17.8 million to run schools, about $12,575 per student, plus $2.2 million on buildings and equipment. Money in: $14 million local (mostly property tax), $6.7 million state, $1.3 million federal. Long-term debt: $13.1 million.
Spent $24.6 million — $19.4 million to run schools, about $14,465 per student, plus $2.6 million on buildings and equipment. Money in: $10.7 million local (mostly property tax), $8.2 million state, $2 million federal. Long-term debt: $12.6 million.
Spent $26.5 million — $23.2 million to run schools, about $25,444 per student, plus $1.9 million on buildings and equipment. Money in: $12.5 million local (mostly property tax), $14.3 million state, $1.3 million federal. Long-term debt: $322,000.
Spent $12.9 million — $11.6 million to run schools, about $15,386 per student, plus $319,000 on buildings and equipment. Money in: $7.4 million local (mostly property tax), $5.8 million state, $907,000 federal. Long-term debt: $8.4 million.
And 1 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 Miami County about $29 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.
312 bridges in Miami County: 218 in good condition, 76 fair, and 18 poor (5.8%). “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.
| KESSLER-FREDERICK over STONER DITCH · built 1954 | 3,227 vehicles a day |
| SWAILES over BOONE CREEK · built 1961 | 2,062 vehicles a day |
| SWAILES over BOONE CREEK · built 1963 | 2,062 vehicles a day |
| PIQUA-LOCKINGTON over MIAMI RIVER · built 1972 | 1,373 vehicles a day |
| RANGE LINE over BRUSH CREEK · built 1962 | 1,244 vehicles a day |
| FENNER over POSSUM RUN · built 1941 | 1,077 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $30 million of work in Miami County in fiscal 2025, about $276 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 Miami 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 Miami County built: brayden.ozark@gmail.com.
More of Ohio: the state government and every county in Ohio.
Nearby counties: Shelby County (20 mi) · Montgomery County (21 mi) · Darke County (21 mi) · Champaign County (25 mi) · Clark County (25 mi) · Greene County (31 mi).