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 24, 2026 and October 9, 2026.
Jefferson County, Montana, has about 13,000 residents (2024 Census Bureau estimate), and arrests there are reported to the FBI by the Jefferson County Sheriff's Office. An arrest leaves the same records whoever makes it: the arresting agency's report, the record of anyone held at the county jail, and, if the County Attorney files charges, a case in the Jefferson County District Court. This guide says who keeps each one, what it costs and who may see it, with the arrest counts each agency reported.
This guide covers who makes arrests, how many arrests, booking and the jail, finding an arrest, copies, cities and common questions.
Related guides: Jefferson County public records, Montana arrest records, Montana inmate search and Montana criminal records.
Who Makes Arrests in Jefferson County
The Jefferson County Sheriff's Office is the county agency that reports arrests to the FBI for Jefferson County. It reported 121 arrests for 2025.
How Many Arrests The Jefferson County Sheriff's Office Reports
The FBI publishes every agency's monthly arrest counts on the Crime Data Explorer. These are the full-year totals, all offenses, as the FBI held them on October 8, 2026; a year with months missing or not reported is left out.
- Jefferson County Sheriff's Office: 121 for 2025, 114 for 2024, 86 for 2023, 121 for 2022, 61 for 2021 and 92 for 2020.
The Jefferson County Sheriff's Office's 121 arrests in 2025 were up 6.1 percent from 114 in 2024.
Through August 2026, Jefferson County Sheriff's Office reported 87 arrests, against 81 in the same months of 2025.
Booking: Where People Arrested in Jefferson County Are Held
A person kept in custody after an arrest in Jefferson County is held at the county jail, whichever agency made the arrest, apart from the short stay some city departments' own holding cells allow; a person cited and released at the scene is not booked at all. The jail's record of each person held, with the charges, is a public record of the arrest, and the court file takes over from there.
On an average day in 2021 the jail held about 7 people, down from about 15 in 2019. Its rated capacity in 2019, the last year with a capacity figure, was 24 beds, and it ran at 62 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
SearchSystems opened and checked the jail page of the Jefferson County Sheriff's Office at jeffersoncountysheriffmt.gov/detention-center (page title: Jefferson County Detention Center | Jefferson County Sheriff's Office), phone (406) 225-4078, 110 S. Washington St. Boulder, MT 59632, Tuesday, Wednesday, Sunday: 9AM - 6PM, which answered when SearchSystems opened it on October 9, 2026.
A sentence of more than a year is served in state prison; the Montana Department of Corrections lists its inmates at offendersearch.mt.gov/conweb.
How to Find Out About an Arrest in Jefferson County
Whether someone was arrested in Jefferson County, and what came of it, shows up in two places: the case index of the Jefferson County District Court, which shows whether charges were filed and the next court date (the court records page SearchSystems verified is at jeffersoncounty-mt.gov/district-court, phone (406) 225-4042); the County Attorney, which decides whether an arrest becomes a charge (its page is at jeffersoncounty-mt.gov/county-attorney, phone (406) 225-4010).
Montana is one of the states that lets anyone look up another person's statewide criminal history: the CHOPRS service lets anyone search public criminal history online by name, through the Montana Department of Justice. That record shows what agencies reported to the state, which is wider than one county's court index but can lag it.
Getting a Copy of an Arrest Record in Jefferson County
An arrest report belongs to the agency whose officer wrote it, and that agency releases it, not the court or the jail. Under the Montana Public Records Act the agency must answer in a timely manner; the statute sets no number of days, and it may charge the actual cost of fulfilling the request.
- An arrest by the Jefferson County Sheriff's Office: ask its records unit, reached through the office at (406) 225-4078.
- A defendant who has been charged gets the report through the case: the County Attorney, (406) 225-4010, handles discovery for pending cases.
- The court file of a case that was filed: the Jefferson County District Court, through the court records page at jeffersoncounty-mt.gov/district-court, phone (406) 225-4042.
- Your own statewide record: the same request described above, for your own name.
The other Jefferson County guides go further: warrants, criminal records, court records, police reports, traffic tickets, DUI, divorce records and property records.
Cities in Jefferson County: Who Reports the Arrests
The FBI lists no city in Jefferson County with an arrest reporting agency of its own; the counts above are the county agencies'.
Wherever in the county the arrest happens, a person kept in custody goes to the county jail and the case goes to the Jefferson County District Court.
Frequently Asked Questions
How many arrests are made in Jefferson County each year?
The Jefferson County Sheriff's Office reported 121 arrests to the FBI for 2025, its latest full year.
How do I find out if someone is in jail in Jefferson County?
Ask the Jefferson County Sheriff's Office at (406) 225-4078; its jail page SearchSystems verified is at jeffersoncountysheriffmt.gov/detention-center.
Where are people arrested in Jefferson County booked?
Those kept in custody go to the county jail, run by the Jefferson County Sheriff's Office; a person cited and released at the scene is not booked.
Are arrest records public in Jefferson County?
The court files of criminal cases are public, and so is the statewide criminal history kept by the Montana Department of Justice: the CHOPRS service lets anyone search public criminal history online by name. The arrest report itself is released by the agency that made the arrest, under the Montana Public Records Act.
How do I get a copy of an arrest report in Jefferson County?
From the agency that made the arrest: the Jefferson County Sheriff's Office for its own arrests, or the agency that reports for the city where it happened. Under the Montana Public Records Act the answer is due in a timely manner; the statute sets no number of days.
Is this the official Jefferson 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.