5,824 people (2024 Census estimate, +0.4% since 2020)
1,311 square miles of land · 4 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.
5 active community water systems list Ontonagon County in the area they serve, reporting 3,758 people served in all (a system that crosses county lines counts its whole population).
| ONTONAGON surface water · local government · MI0005030 | 2,607 served |
| MCMILLAN TOWNSHIP groundwater · local government · MI0002200 | 391 served |
| ROCKLAND TOWNSHIP groundwater · local government · MI0005740 | 350 served |
| BERGLAND TOWNSHIP groundwater · local government · MI0000620 | 210 served |
| INTERIOR TOWNSHIP groundwater · local government · MI0006680 | 200 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 5 people were held in Ontonagon County's jail, in Vera's latest figure (2020), or 154 per 100,000 residents ages 15–64. In 2015 it was about 12.
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 Ontonagon County. School taxes are usually the largest part of a property tax bill.
Spent $4.7 million — $4.3 million to run schools, about $15,804 per student, plus $296,000 on buildings and equipment. Money in: $2.7 million local (mostly property tax), $1.3 million state, $703,000 federal. Long-term debt: $247,000.
Spent $3.3 million — $3 million to run schools, about $18,616 per student, plus $201,000 on buildings and equipment. Money in: $2.3 million local (mostly property tax), $672,000 state, $843,000 federal. Long-term debt: $4.7 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 Ontonagon County about $2.4 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively High; social vulnerability: Relatively High.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
66 bridges in Ontonagon County: 25 in good condition, 31 fair, and 10 poor (15.2%). “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.
| M-28 over WAPATO CREEK · built 1938 | 1,845 vehicles a day |
| US-45 over CLEAR CREEK · built 1931 | 1,648 vehicles a day |
| M-64 over PINE RIVER · built 1968 | 1,032 vehicles a day |
| OLD M-107 over UNION RIVER · built 1976 | 831 vehicles a day |
| OLD M-107 over LITTLE IRON RIVER · built 1967 | 831 vehicles a day |
| OLD M-107 over BIG IRON RIVER · built 1938 | 831 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $14.9 million of work in Ontonagon County in fiscal 2025, about $2,562 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 Michigan 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 Ontonagon 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 Ontonagon County built: brayden.ozark@gmail.com.
More of Michigan: the state government and every county in Michigan.
Nearby counties: Houghton County (32 mi) · Gogebic County (34 mi) · Baraga County (44 mi) · Vilas County, WI (55 mi) · Keweenaw County (57 mi) · Iron County (58 mi).