Montana gives a misdemeanor DUI a statutory deadline: after you enter a plea, the State has 6 months to bring the case to trial, or the court must dismiss it with prejudice, unless you postponed the trial or the State shows good cause (MCA § 46-13-401(2)). A felony DUI has no such number. It is governed by the constitutional right to a speedy trial, which Montana courts apply through a four-factor test. This page is part of our Montana DUI Guide and expands a point made briefly in the DUI court process overview.
The Six-Month Rule for Misdemeanors
The text is one sentence: "After the entry of a plea upon a misdemeanor charge, the court, unless good cause to the contrary is shown, shall order the prosecution to be dismissed, with prejudice, if a defendant whose trial has not been postponed upon the defendant's motion is not brought to trial within 6 months" (MCA § 46-13-401(2)).
A first, second, or third DUI is a misdemeanor, so this is the rule for most DUI cases in justice, city, and municipal court. The Montana Supreme Court has read it as a two-condition test. A misdemeanor will be dismissed under the statute only if (1) the defendant has not asked for a postponement and (2) the State has not shown good cause for the delay (City of Helena v. Roan, 2010 MT 29, paragraph 9).
When the Clock Starts
The six months run from "the entry of a plea." That is typically the day of your arraignment, when you plead not guilty. The statute does not count the days between the arrest and the plea, so a person who was cited in March and entered a plea in April measures from April.
This is a common point of confusion, because websites often describe the rule as six months from arrest. It is not. Find the date your plea was entered on the court's docket or your paperwork and count from there.
What Takes the Rule Away
A postponement on your motion. The statute protects only a defendant "whose trial has not been postponed upon the defendant's motion." The Supreme Court has read that broadly. In Roan it said that "any pretrial motion for continuance filed by a defendant which has the incidental effect of delaying the trial beyond the six month time limit could be said to 'postpone trial'" for purposes of the statute (paragraph 10). A request to move the omnibus hearing, not just the trial, can therefore matter.
Good cause.The court need not dismiss if "good cause to the contrary is shown." The statute does not define good cause. In Roan, the medical unavailability of a prosecution witness qualified. Whether a crowded court calendar, a late lab report, or some other reason qualifies in a given case is argued to the judge on the facts.
A plea agreement also ends the question in practice. A person who pleads guilty is not brought to trial at all.
The Constitutional Right, and Felony DUI
Separately from the statute, the Montana Constitution guarantees an accused "a speedy public trial" in "all criminal prosecutions" (Article II, Section 24). For a felony DUI, which the six-month statute does not cover, this is the governing rule.
The framework comes from State v. Ariegwe, 2007 MT 204. A court balances four factors (paragraphs 106 to 112):
- The length of the delay. If the interval between accusation and trial is less than 200 days, the claim is denied without further analysis. At 200 days or more, the full test is triggered, and the longer the delay runs past that point, the heavier the State's burden to justify it.
- The reasons for the delay. Each period is attributed to the State or the accused. Delay not shown to be caused or waived by the accused is attributed to the State by default. Bad-faith delay weighs most heavily, and institutional delay such as a crowded docket weighs less.
- The accused's responses to the delay. Whether you objected to or went along with continuances, considered in context.
- Prejudice to the accused. Pretrial incarceration, prolonged anxiety and disruption, and harm to the ability to present a defense.
No one factor is dispositive (Ariegwe, paragraph 112). The 200-day figure is a threshold for looking closely, not a deadline that produces a dismissal by itself.
The Two Tests Side by Side
| Six-month statute | Constitutional test | |
|---|---|---|
| Source | MCA § 46-13-401(2) | Montana Constitution, Article II, Section 24, as applied in State v. Ariegwe |
| Applies to | Misdemeanor charges | All criminal prosecutions. It is the only test for a felony. |
| Clock starts | At the entry of a plea | At the accusation |
| Number | 6 months | 200 days triggers the analysis. It is not a deadline. |
| What defeats it | A postponement on the defendant's motion, or good cause shown | A balancing of four factors, with no single one controlling |
Deciding Whether to Ask for More Time
The deadline protects you, but it is not always the most valuable thing in the case. There are good reasons a defense needs time: discovery arrived late, an independent analysis is pending, a motion to suppress needs a hearing, or a witness is unavailable. Going to trial unprepared to preserve a clock is rarely a good trade.
What matters is that the choice is deliberate. Before any continuance is requested, ask your attorney three questions. Will this move the trial past six months from the plea? If so, is what we gain worth giving up the statutory deadline? And is there a way to get what we need without moving the trial? The court decides continuance motions in its discretion and is directed to see that cases are tried with due diligence, consistent with both sides' right to a speedy trial (MCA § 46-13-202(3)).
If the State is the one asking for delay, the response matters too. An objection on the record is part of how a later court evaluates both the statutory and the constitutional claim.
What This Rule Does Not Cover
The six-month statute is about the criminal trial. It does not extend or shorten the separate 30-day deadline to challenge a refusal suspension in district court (MCA § 61-8-1017(1)), and it says nothing about how quickly a sentence must be completed. It also does not address what happens to the clock in a case that is appealed from a lower court for a new trial. If your case is in that position, ask your attorney how the district court treats it. Our page on how long a DUI case takes puts these deadlines on one timeline.
This page explains Montana law in general as of the 2025 Montana Code Annotated and the decisions cited. Whether a deadline has run in your case depends on its docket. It is not legal advice about your specific case.