Montana DUI Guide

How an Out-of-State Prior DUI Counts in Montana

A conviction from another state does not count just because it was called a DUI there. The question is whether that state's statute is similar to Montana's.

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.

Montana Bar #122346+ years as an attorney, with over two decades working in the lawReviewed by Ashley HurlbertLast reviewed: October 9, 2026

Key Takeaways: How an Out-of-State Prior DUI Counts in Montana

A conviction in another state, or on a federally recognized Indian reservation, can count as a prior DUI in Montana (MCA § 61-8-1011(1)(a)).
It counts only if it was for a violation of a similar statute. The label the other state used does not decide that.
The Montana Supreme Court has said statutes are not similar when the other state allows a conviction on a lesser standard of impairment than Montana requires.
For a second offense, the prior counts if less than 10 years passed between that conviction and the new offense. For a third or later, every prior counts.
A counted prior changes more than jail time: the license suspension, treatment, 24/7 monitoring, and whether the case is a felony.
Whether a specific prior counts is a legal question a defense lawyer can challenge before sentencing.

A prior DUI from another state counts in a Montana case if it was a final conviction under a statute similar to Montana's and it falls within the lookback rule. Both parts can be contested. The first turns on a comparison of the two states' laws. The second turns on dates. This page explains each and what a counted prior changes. It is part of our Montana DUI Guide and goes deeper than our general page for out-of-state drivers.

What the Statute Says

MCA § 61-8-1011(1)(a) defines "conviction" for counting prior DUI offenses. It includes:

a final conviction in Montana, in another state, or on a federally recognized Indian reservation;
a forfeiture of bail or collateral, not vacated, in any of those places; and
a conviction for DUI under Montana law, for "a similar offense under previous laws of this state or the laws of another state," or for "a violation of a similar statute or regulation in another state or on a federally recognized Indian reservation."

The word doing the work is similar. The statute does not list which states qualify, and it does not say that anything called DUI, DWI, or OWI elsewhere counts.

The Similar-Statute Test

The Montana Supreme Court has addressed this more than once. The decisions were written under the earlier section number, § 61-8-734, which used the same "similar statute or regulation in another state" wording that now appears in § 61-8-1011.

In State v. Lund, 2020 MT 53, the defendant had three prior DUI convictions from Alaska and argued they could not make his Montana charge a felony. The Court restated its rule: if another state's law allows a person to be convicted using a lesser standard of impairment than would be required for a conviction in Montana, the statutes are not similar (¶ 8). It then compared the two standards. Montana defines "under the influence" as an ability to safely operate a vehicle that has been diminished. Alaska's standard, as its courts had read it, required impairment that leaves a driver unable to operate with the caution of an ordinarily prudent person. The Court held that Alaska's standard was not a lesser one, so the convictions counted (¶¶ 13 to 15).

Lund also describes the case that went the other way. In State v. McNally, 2002 MT 160, the prior convictions were for Colorado's "driving while ability impaired," an offense that applied when the ability to drive was affected to the slightest degree. Montana had no comparable offense, and those convictions did not count (Lund, ¶ 11).

Three practical points follow from those opinions:

The comparison is between legal standards, not names. Different wording can still be similar.
A lesser impaired-driving offense in another state is the classic candidate for a prior that does not count.
Whether a prior can be used to enhance a sentence is a question of law (Lund, ¶ 6), so it can be raised by motion before sentencing.

The Lookback: 10 Years, Then Lifetime

A similar conviction still has to fall inside the time rule in MCA § 61-8-1011(1)(b). An offender is treated as previously convicted if less than 10 years have elapsed between the commission of the present offense and a previous conviction. That is measured from the earlier conviction date to the date of the new offense, not arrest to arrest.

The exception is large. If the present offense is the person's third or subsequent offense, all previous convictions must be used. So a single 15-year-old conviction from another state does not make a new Montana case a second offense. Two old convictions, both similar, can make it a third. Our page on how long a DUI stays on your record walks through the lookback in more detail.

What a Counted Prior Changes

Area	Effect	MCA
Penalty tier	Second and third offenses carry higher jail minimums and fines than a first.	§ 61-8-1007
Felony DUI	A combination of three or more prior convictions makes the new offense a felony.	§ 61-8-1008(1)(a)
Aggravated-level sentence	A prior or pending DUI from another state that meets Montana's aggravated DUI definition moves the new sentence to the aggravated schedule.	§ 61-8-1007(1)(c), (2)(c)
License suspension	A second offense within the lookback period means 1 year, with limits on a probationary license.	§ 61-5-208(2)(b)(ii)
Treatment	A second or later conviction requires chemical dependency treatment, not only the education course.	§ 61-8-1009(1)(b)
24/7 Sobriety Program	A court may compel participation if there is a similar conviction from another state in the prior 10 years.	§ 44-4-1205(4)
Testing after a refusal	A prior conviction or prior refusal in another jurisdiction removes the bar on testing an arrested person who refuses.	§ 61-8-1016(4)(a)

The penalty numbers for each tier are on our second and third DUI page, our felony DUI page, and the DUI penalties chart.

Priors That Raise Their Own Questions

Under-21 convictions. A conviction under Montana's own under-21 section may not be counted as a prior (MCA § 61-8-1007(3)(b)). The statute does not say how a zero-tolerance conviction from another state is treated, so that is an argument to raise, not a settled rule.
Diversions, deferrals, and set-aside convictions. Montana counts a "final conviction" as its criminal code defines it, which refers to a judgment of conviction and sentence entered on a plea or verdict (MCA § 45-2-101). Whether another state's diversion or dismissed-after-probation outcome fits that definition depends on what the other court actually entered.
Bail forfeitures. An unvacated forfeiture of bail in another state counts as a conviction under the statute.
Pending cases. Since October 1, 2025, a pending offense counts if it results in a conviction before sentencing on the present one (MCA § 61-8-1011(1)(a)(iii)).
Tribal court convictions. A conviction on a federally recognized Indian reservation is treated the same way as one from another state.

How to Prepare

The prosecution usually works from a driving record or criminal history printout, which may show only a short description. The defense needs more than that: the charging document, the judgment, the exact statute and subsection, and the dates of offense and conviction. With those, a lawyer can compare the other state's law as it read at the time with Montana's. If you are also dealing with a license from another state, see our page on out-of-state licenses and the Compact.

This page explains Montana law in general as of the 2025 Montana Code Annotated. It is not legal advice about your specific case.

Montana DUI Guide DUI Defense DUI Under 18: Court, License & Parents Moving Out of State After a DUI MIP vs. Under-21 DUI College Students & DUI

FAQ

How an Out-of-State Prior DUI Counts in Montana FAQ

Does a DUI from another state count as a prior in Montana?

It can. Montana's definition of a prior conviction includes a final conviction in another state for a similar offense, or for a violation of a similar statute or regulation (MCA § 61-8-1011(1)(a)). Whether a particular conviction qualifies depends on the other state's statute and on the dates. See our second and third DUI page for what a counted prior does to the penalties.

What makes another state's DUI law similar to Montana's?

The Montana Supreme Court compares the impairment standards. In State v. Lund, 2020 MT 53, it held Alaska's DUI statute was similar because it required a reduction in the ability to drive, as Montana's does. The Court contrasted its earlier McNally decision, where a Colorado offense that punished impairment to the slightest degree was not similar.

My out-of-state DUI was more than 10 years ago. Does it still count?

For a second offense, no, if 10 years or more passed between that conviction and the commission of the new offense. For a third or later offense the 10-year limit does not apply and all previous convictions must be used (MCA § 61-8-1011(1)(b)). So an old conviction can drop out when you have one prior and come back in when you have two.

Does a reduced charge in another state, such as driving while ability impaired, count?

Not automatically. In the Colorado example the Montana Supreme Court discussed in Lund, a driving-while-ability-impaired conviction did not count because Montana had no comparable offense. Each state's statute has to be compared on its own terms, and legislatures change them, so your lawyer should check the version in force when you were convicted.

Can I challenge whether my prior counts?

Yes. Whether a prior conviction can be used to enhance a sentence is a question of law. The usual issues are whether the record shows a final conviction, whether the other state's statute was similar, and whether the dates fall inside the lookback. Bring every document you have from the old case to your lawyer.

Does an Old Conviction From Another State Count?

Bring the paperwork from the earlier case and we will look at the statute and the dates. Call 406-830-3060 for a confidential consultation.

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