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 2, 2026.
Cascade County, Montana, has about 85,000 residents (2024 Census Bureau estimate). A DUI arrest in Cascade County starts two cases, a criminal case in a Justice or Municipal Court and a license case before the Motor Vehicle Division, and leaves three records. This guide follows the arrest from the roadside to the court file and the driving record.
This guide covers the law, the arrest, booking, the court case, the license case, the records and common questions.
Related guides: Cascade County public records, Cascade County arrest records, Cascade County warrants, Cascade County inmate search, Cascade County criminal records, Montana arrest records and Montana inmate search.
The DUI Law in Montana
Drunk driving is charged as DUI in Montana, at a blood alcohol level of 0.08 or more.
Driving in Montana is consent to a breath or blood test when an officer has cause to suspect DUI; the license case that follows a refusal or a failed test is run by the Motor Vehicle Division, separately from the criminal case.
Who Makes DUI Arrests in Cascade County
The Cascade County Sheriff's Office and the agency that reports for Great Falls make the DUI arrests in Cascade County.
The FBI's agency list also places one more agency in Cascade County: the Great Falls International Airport Authority (other agency).
Together, the two agencies in Cascade County with all twelve months of 2025 on file reported 3,602 arrests to the FBI that year, all offenses together; the FBI's count for Cascade County does not break DUI out.
Booking After a DUI Arrest in Cascade County
A driver arrested for DUI and kept in custody goes to the county jail, whichever agency made the arrest. The jail, run by the Cascade County Sheriff's Office, held about 430 people on an average day in 2023 by the Vera Institute of Justice's count and has a custody page SearchSystems verified at cascadecountymt.gov/314/Inmate-Roster, phone 406-454-6820. The Cascade County inmate search guide covers the jail in full.
The Court Case
A DUI charge from Cascade County is heard in a Justice or Municipal Court; the County Attorney or, in a municipal court, the city's own prosecutor brings it.
The court records page SearchSystems verified for the county is at cascadecountymt.gov/158/Clerk-of-Courts-Office, phone (406) 604-7796.
Montana has no single public index of every trial court case; each court's records are looked up through that court.
The License Case
A DUI arrest starts two cases: the criminal one above and an administrative one over the license, run by the Motor Vehicle Division. The driving record, kept by the Montana Motor Vehicle Division, carries the result of both.
The Records a DUI Leaves
- The arrest report: from the agency that made the arrest, under the Montana Public Records Act.
- The court file: from a Justice or Municipal Court, kept by the Clerk of District Court.
- The driving record: from the Montana Motor Vehicle Division.
More on each: Cascade County arrest records, Cascade County police reports and Cascade County court records.
Frequently Asked Questions
What is the DUI limit in Montana?
0.08 percent blood alcohol.
Where is a DUI case from Cascade County heard?
In a Justice or Municipal Court. The court records page SearchSystems verified for the county is at cascadecountymt.gov.
Where is a person arrested for DUI in Cascade County held?
At the county jail, run by the Cascade County Sheriff's Office, if kept in custody.
Who handles the license after a DUI arrest in Montana?
The Motor Vehicle Division, in an administrative case separate from the court case.
Is this the official Cascade 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.