Montana DUI Guide
What the law says, what happens after an arrest, what it costs, and how to choose a defense. Written by Missoula DUI attorneys, with the statute cited for every rule.
Written by
Misty Gaubatz, Partner, A&M Law
Licensed Montana attorney and co-founder of A&M Law. Over two decades in the practice of law focusing on family law, criminal defense, and DUI defense, with federal and state court experience and a Certificate in Mediation.
People look up DUI law at three different moments. Some are curious about a rule: whether you can be charged for sleeping in a parked car, or what a checkpoint is allowed to do. Some were arrested last week and want to know what happens next and what it will cost. And some have decided they need help and are working out who to hire.
This guide is organized around those three moments. Each article answers one question, cites the section of the Montana Code Annotated it relies on, and says so when the law does not give a clear answer. Much of what is published online about Montana DUI law still cites statutes that were replaced in 2022, so we have tried to be exact about what the current law says.
If you already know the charge you are facing, our Missoula DUI defense page and the charge-specific pages at the bottom of this one are the faster route. If you would rather talk it through, call 406-830-3060.
Understand the Law
What counts as a DUI in Montana, where the law applies, and the terms you will see on a citation.
DUI vs. DWI: Montana Terms & Limits
Montana calls it DUI. The legal limits, the kinds of DUI charge, and the words on your paperwork.
Sleeping in Your Car: Actual Physical Control
You can be charged without driving. How Montana courts decide who was in control of a vehicle.
DUI on a Horse, Bike, ATV, or Boat
Which vehicles Montana's DUI law reaches, which it does not, and the separate boating law.
Checkpoints & Open Containers
When an officer can stop you, what a roadblock may check, and the open container rule.
Prescription & Drug DUI
A valid prescription is not a free pass. Montana's drug limits and what the State must prove.
After an Arrest
What happens in court, what a conviction costs, and what it can touch outside the courtroom.
The DUI Court Process
From the first appearance to trial or a plea, in Missoula's municipal and justice courts.
How Long a DUI Stays on Your Record
The 10-year lookback, the lifetime rule for a third offense, and what expungement can do.
What a DUI Costs
Fines, license fees, the assessment and classes, monitoring, and the costs no statute lists.
Ignition Interlock & Probationary Licenses
When a court can let you drive during a suspension, and on what conditions.
DUI Classes, Assessment & Treatment
The chemical dependency assessment every conviction requires, and what follows from it.
DUI With a Crash or a Child in the Car
How an injury, a death, or a young passenger changes the charge and the penalty.
Traveling to Canada After a DUI
Why a single DUI can stop you at the border, and the two ways to be allowed in.
Jobs, Licenses, Gun Rights & Custody
What a DUI does and does not affect: work, professional licenses, firearms, parenting plans.
Choosing a Defense
Whether you need a lawyer, what one costs, and how a DUI charge is actually challenged.
Do I Need a Lawyer for a First DUI?
Representing yourself, the public defender, or a private attorney: an honest comparison.
What a DUI Lawyer Costs in Montana
How DUI defense fees are set, what drives them, and the questions to ask before you hire.
DUI Defenses: Dismissal & Reduction
The stop, the tests, and the machine. Where DUI cases are won, and what a reduction means.
The Numbers That Run a Montana DUI Case
Most of a DUI case moves at the court's pace. These time periods do not, and the short ones start at the arrest.
| Time | What it governs | MCA |
|---|---|---|
| 12 hours | After a license is seized at arrest, the temporary driving permit takes effect 12 hours after it is issued. | § 61-8-1016 |
| 5 days | How long that temporary permit is valid. | § 61-8-1016 |
| 30 days | The time to petition the district court to challenge a test-refusal suspension. | § 61-8-1017 |
| 6 months | The license suspension for a first DUI conviction, and separately for a first refusal. | §§ 61-5-208, 61-8-1032 |
| 1 year | The time the State generally has to file a misdemeanor charge. | § 45-1-205 |
| 10 years | How long a prior DUI counts toward a second offense. For a third, every prior counts. | § 61-8-1011 |
Pages for a Specific DUI Charge
The guide above answers questions. These pages cover the charges and proceedings we defend, one at a time.
- DUI Defense
- First-Offense DUI
- Second & Third DUI
- Felony DUI (4th+)
- Aggravated DUI
- Test Refusal & Implied Consent
- License Suspension & Hearings
- 24/7 Sobriety Program
- THC / Marijuana DUI
- Field Sobriety Tests
- Under-21 DUI
- CDL / Commercial Driver DUI
- Out-of-State Drivers
- What Happens After a DUI Arrest in Montana?
- First DUI vs. a Repeat DUI in Montana
Montana DUI Guide, Common Questions
What is the legal limit for DUI in Montana?
Is a first DUI a misdemeanor in Montana?
Will I lose my license right away after a DUI arrest?
Can a Montana DUI be deferred or expunged?
Do I need a lawyer for a first DUI?
Who wrote this guide?
Arrested for DUI in Western Montana?
The license deadline starts at the arrest. Call 406-830-3060 for a confidential consultation with a DUI defense attorney.