Montana License Plate Reader Laws (2026)

Montana has a specific ALPR law, and it starts from a ban. Under Mont. Code Ann. § 46-5-117, "an agency or employee of the state or any subdivision of the state may not use, either directly or indirectly, a license plate reader on any public highway," except in listed situations. The main exception lets law enforcement use readers under a written policy, annual audits and seven listed purposes, and § 46-5-118 sets a 90-day limit on keeping captured data.

Information reviewed September 30, 2026.

For related pages, see the Montana entry in the state comparison, the ALPR laws hub, Are Flock cameras legal?, What are Flock cameras?, and our Montana surveillance camera laws guide.

What does the Montana ban cover?

The statute's definition of "license plate reader" is broad. It covers any device principally designed and primarily used to determine the ownership, location, route or occupant identity of a vehicle, and it lists transponders, cell phones, GPS, toll systems and automated license plate readers.

The ban is written for state and local government actors. This page did not identify a Montana provision in these two sections that addresses homeowners associations or businesses running their own readers.

What exceptions does Montana allow?

Section 46-5-117(2) allows four categories of use:

• The Department of Transportation or an incorporated city or town may collect planning data, and may run regulated parking enforcement. Planning data must be anonymous, and data collected without a search warrant or outside recognized exceptions to the warrant requirement "may not be used to investigate or prosecute an individual or as evidence in court."
• The Department of Transportation may use readers in screening operations such as virtual ports of entry, weigh stations, weigh-in-motion and transponder prescreening.
• An agency may track its own vehicles and equipment.
• State or local law enforcement may use readers under the conditions in paragraph (2)(d).

What must law enforcement do before using a reader?

A law enforcement agency using a reader system "shall adopt and publicize a written policy governing its use before the automatic license plate reader system is operational." The policy must cover databases compared, retention, sharing with other agencies, operator training, supervisory oversight, access and security, and access to data from readers the agency does not operate, among other subjects.

At least annually, the agency must audit its reader use and effectiveness and report findings to the agency head. It must keep a record of the users who access reader data, and "[t]he record must be maintained indefinitely." Maintenance and calibration records must be kept on file.

When may a Montana agency use a reader?

Use is limited to official law enforcement purposes. A reader "must be used by a law enforcement agency only to scan, detect, and identify a license plate number for the purpose of identifying a vehicle" that is:

• stolen;
• associated with a wanted, missing or endangered person;
• registered to a person with an outstanding warrant;
• in violation of commercial trucking requirements;
• involved in case-specific criminal investigative surveillance;
• involved in a homicide, shooting or other major crime; or
• in the vicinity of a recent crime and possibly connected to it.

Data must be obtained, accessed, preserved or disclosed only for law enforcement or criminal justice purposes. The system must be updated from its databases every 24 hours if an update is available, or as soon as practicable after one becomes available.

Is a plate reader match enough for a traffic stop?

No. The statute says "[a] positive match by a license plate reader alone does not constitute reasonable suspicion as grounds for a law enforcement officer to stop a vehicle." The officer must develop independent reasonable suspicion, or immediately confirm visually that the plate matches the image and confirm by other means that the vehicle meets one of the listed criteria.

How long can Montana keep plate data?

Under § 46-5-118, captured plate data from a system operated by or for law enforcement "may not be preserved for more than 90 days after the date that the data is captured."

Three exceptions exist. One is a preservation request supported by a sworn statement that gives the camera location, plate, dates, specific and articulable facts, and the case and parties. The others are a state search warrant under § 46-5-220 and a federal search warrant. Preserved data must be destroyed one year after the initial preservation request unless another request is received, which resets the year.

Can you request ALPR records in Montana?

Section 46-5-118(5) says captured plate data "is a public record but is protected from disclosure under the provisions of Title 2, chapter 6, parts 10 through 12, except to the person to whom the license plate is registered." Disclosure is not required if the agency determines it would compromise an ongoing investigation. Captured plate data gathered by law enforcement may not be sold except as provided in § 46-5-117.

This page did not review the Title 2, chapter 6 exemption text, so it does not decide how those provisions apply to a particular request.

What are the penalties?

A public employee or officer who violates section 46-5-117 "is subject to the applicable penalties provided for in Title 2, chapter 2." The text read has no separate criminal penalty and no private right of action.

Have Montana courts or local governments addressed ALPR?

The research for this page did not find a Montana court ruling, Attorney General opinion or local deployment record on this subject. That is a statement about what was found, not proof that none exists. Montana Highway Patrol and Department of Transportation policies, local council actions and Montana Constitution privacy case law were not researched. The Legislature holds regular sessions only in odd-numbered years, and the 2025 Montana Code shows no amendment to either section since 2017. The Daily Montanan reported in September 2026 that Sen. Daniel Zolnikov plans, if reelected, to introduce bills in the next session requiring public hearings before the technology is installed, changing how long public entities can hold data and how they collect and share it, and limiting how private systems share data with government and law enforcement. Those proposals are not law.

Frequently asked questions

Last updated: September 30, 2026. Statutes cited reflect the text reviewed on September 30, 2026.

One general law may be relevant. The Montana Consumer Data Privacy Act applies, under § 30-14-2803, to businesses that control or process the personal data of at least 25,000 consumers, or at least 15,000 while deriving more than 25% of gross revenue from selling personal data, and under § 30-14-2804 it does not apply to any "body, authority, board, bureau, commission, district, or agency of this state or any political subdivision of this state." The act does not mention license plates, and this page does not decide whether it reaches a private plate reader operator.

A separate 2025 statute limits buying data. Under § 46-5-603, except as provided in the investigative subpoena and search warrant parts of Title 46, "pursuant to a search warrant or investigative subpoena issued by a court, a governmental entity may not purchase" listed categories of data, including "contents of a communication from a tracking device, including an electronic or mechanical device that permits the tracking of the movement of a person or object" and "precise geolocation data as defined in 30-14-2802." That definition covers information that "directly identifies the specific location of an individual with precision and accuracy within a radius of 1,750 feet." The section does not mention license plate readers, and this page does not decide whether it reaches an agency's purchase of, or subscription to, commercially collected plate reader data.

Frequently Asked Questions

Is it legal for Montana police to use license plate readers?

Section 46-5-117 bars state and local agencies from using a license plate reader on any public highway, with exceptions. Law enforcement may use one under a written policy and for seven listed purposes.

How long can Montana keep license plate reader data?

Captured data from a law enforcement system may not be preserved more than 90 days after capture, unless a sworn preservation request, state search warrant or federal search warrant applies.

Can an officer stop a car just because a reader flagged it?

No. A positive match alone does not constitute reasonable suspicion. The officer must develop independent reasonable suspicion or confirm the match by other means.

Are Montana plate reader records public?

Captured plate data is a public record but is protected from disclosure, except to the person to whom the plate is registered.

Does the Montana law apply to private companies or HOAs?

The ban is written for state and local government agencies and employees. This page did not identify a provision in these sections that addresses private operators.

What is the penalty for violating the law?

A public employee or officer who violates section 46-5-117 is subject to the penalties in Title 2, chapter 2. The text read has no separate criminal penalty.