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 on September 24, 2026.
Yellowstone County, Montana, has about 172,000 residents (2024 Census Bureau estimate). A person kept in custody after an arrest in Yellowstone County is held at the county jail, run by the Yellowstone 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: Yellowstone County public records, Yellowstone County arrest records, Yellowstone County warrants, Yellowstone County criminal records, Yellowstone County court records, Montana arrest records and Montana inmate search.
Finding Someone in Custody in Yellowstone County
The county jail, run by the Yellowstone County Sheriff's Office, holds everyone kept in custody after an arrest in Yellowstone County, from every agency.
SearchSystems opened and checked the jail page of the Yellowstone County Sheriff's Office at yellowstonecountymt.gov/sheriff/detention/dcsearch.asp (page title: Yellowstone County, Montana), which answered when SearchSystems opened it on September 24, 2026.
That page is the office's jail information page rather than a roster.
The Yellowstone County Jail by the Numbers
On an average day in 2021 the jail held about 450 people, down from about 470 in 2019. Its rated capacity in 2019, the last year with a capacity figure, was 383 beds, and it ran at 124 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
Yellowstone County has about 172,000 residents (2024 Census Bureau estimate), so the jail holds about 26 people for every 10,000 residents.
Who Books People Into the Yellowstone County Jail
The Yellowstone County Sheriff's Office and the agencies that report for Billings and Laurel make the arrests that end in a booking in Yellowstone County.
The FBI's agency list also places one more agency in Yellowstone County: Montana State University at Billings (campus police).
The largest arrest counts reported to the FBI were Billings's 3,930 for 2025, the Yellowstone County Sheriff's Office's 787 for 2025 and Laurel's 108 for 2025.
Together, the three agencies in Yellowstone County with all twelve months of 2025 on file reported 4,825 arrests to the FBI that year. 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 Yellowstone 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 Montana Department of Corrections lists its inmates at offendersearch.mt.gov/conweb.
Frequently Asked Questions
How do I find an inmate in Yellowstone County?
Ask the Yellowstone County Sheriff's Office; its jail page SearchSystems verified is at yellowstonecountymt.gov.
How many people are in the Yellowstone County jail?
About 450 on an average day in 2021, the latest year in the Vera Institute's jail data, against a rated capacity of 383 beds.
Where do people sentenced to prison in Yellowstone County go?
To a facility of the Montana Department of Corrections; its inmate locator is at offendersearch.mt.gov/conweb.
Is this the official Yellowstone 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.