Reviewed and updated October 9, 2026 by the SearchSystems.net editorial team. The arrest counts are the ones each agency reported to the FBI, as the FBI held them on October 8, 2026. The jail figures are from the Vera Institute of Justice's Incarceration Trends data. Every office link was opened and checked against the office's own site between September 23, 2026 and September 30, 2026.
Ontonagon County, Michigan, has about 5,800 residents (2024 Census Bureau estimate). A person kept in custody after an arrest in Ontonagon County is held at the county jail, run by the Ontonagon County Sheriff's Office, and the jail's record of each person held is a public record. This guide says where to look for someone in custody, what the jail holds and who books people into it.
This guide covers the search, the jail, who books people, state prison and common questions.
Related guides: Ontonagon County public records, Ontonagon County arrest records, Ontonagon County warrants, Ontonagon County police reports, Ontonagon County property records, Michigan arrest records and Michigan inmate search.
Finding Someone in Custody in Ontonagon County
A person kept in custody after an arrest in Ontonagon County is held at the county jail, run by the Ontonagon County Sheriff's Office, whichever agency made the arrest.
SearchSystems opened and checked the jail page of the Ontonagon County Sheriff's Office at ontonagoncounty.org/county-offices/sheriff-department (page title: Sheriff Department | Ontonagon County), phone 906-884-4901, which answered when SearchSystems opened it on September 30, 2026.
That page is the office's jail information page rather than a roster, so a search for a particular person goes through the office at 906-884-4901.
The Ontonagon County Jail by the Numbers
On an average day in 2020 the jail held about 5 people, down from about 12 in 2019. Its rated capacity in 2019, the last year with a capacity figure, was 19 beds, and it ran at 63 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
Ontonagon County has about 5,800 residents (2024 Census Bureau estimate), so the jail holds about 8 people for every 10,000 residents.
Who Books People Into the Ontonagon County Jail
The Ontonagon County Sheriff's Office makes the arrests that end in a booking in Ontonagon County.
The FBI's agency list also places one more agency in Ontonagon County: the Ontonagon County State Police (state police).
The Ontonagon County Sheriff's Office reported 11 arrests to the FBI for 2025. Those kept in custody were booked into the county jail; a person cited and released at the scene was not.
The counts, agency by agency and year by year, are in Ontonagon County arrest records.
From the Jail to State Prison
A sentence of more than a year is served in state prison, not the jail; the Michigan Department of Corrections lists its inmates at mdocweb.state.mi.us/otis2.
Frequently Asked Questions
How do I find an inmate in Ontonagon County?
Ask the Ontonagon County Sheriff's Office at 906-884-4901; its jail page SearchSystems verified is at ontonagoncounty.org.
How many people are in the Ontonagon County jail?
About 5 on an average day in 2020, the latest year in the Vera Institute's jail data, against a rated capacity of 19 beds.
What is the phone number for the Ontonagon County jail?
906-884-4901, the number on the page of the Ontonagon County Sheriff's Office SearchSystems verified.
Where do people sentenced to prison in Ontonagon County go?
To a facility of the Michigan Department of Corrections; its inmate locator is at mdocweb.state.mi.us/otis2.
Is this the official Ontonagon County website?
No. SearchSystems.net is an independent public records guide, online since 1997. It links to the official county, court and state offices described above and does not hold records, charge for them or take requests.