Montana Uninsured Motorist Coverage 2026: What You Must Know

What Is Montana Uninsured Motorist Coverage?

Uninsured motorist (UM) coverage is a component of your auto insurance policy that pays for your injuries and those of your passengers when the at-fault driver has no liability insurance. Montana law (MCA §61-6-103) requires insurers to offer UM coverage with every auto policy, and policyholders can reject it in writing, but the default is that you have it.

You are required to have UM coverage unless you sign a waiver. In practice, nearly all Montana policies include it. The coverage also extends to family members living in your household and passengers in your vehicle at the time of the crash.

Montana is a fault (tort) state for auto accidents. That means the driver who caused the collision is responsible for your damages. providers often see claims from drivers whose own coverage had to pay because the other driver was uninsured, a situation UM coverage is designed to prevent.

Montana allows something called stacking of uninsured motorist coverage. Stacking means you can combine the UM limits from multiple vehicles on the same policy, or from multiple policies, to increase the total amount available to you after a crash.

1. Determine the per-person and per-accident limits on each vehicle or policy.
2. If the policy is a single policy covering multiple vehicles, stacking typically applies horizontally, you add the per-accident limits together.
3. If you have policies with different insurers (for example, a personal auto policy and a commercial auto policy), vertical stacking may apply, adding the per-person limits.
4. Check your policy declarations page for the phrase "unstacked" or "anti-stacking", some insurers explicitly prohibit stacking by policy language.
5. File your UM claim with your own insurer and be prepared to document the stacking calculation.

A practical example: If you have UM limits of $50,000 per person on two vehicles on the same policy, stacking those limits would give you up to $100,000 in UM coverage for your injuries. The same logic applies for per-accident limits.

Montana courts have generally allowed stacking when policy language is ambiguous. But reading your policy's anti-stacking clause is essential before you assume stacking applies. Some insurers write policies that specifically prohibit stacking, in that case, you cannot combine limits.

If you are hit by a driver without insurance or a hit-and-run driver in Montana, your own UM coverage steps in. The process differs slightly depending on whether you know who hit you.

In a hit-and-run crash: You must report the accident to law enforcement immediately. Montana law requires that you file a police report within 24 hours. Your UM insurer will need the police report to confirm the hit-and-run happened and that you did not identify the driver.

When the at-fault driver is identified but uninsured: The process is the same, except you will have their name and license plate. Your insurer will still handle the claim under your UM coverage. Note that UM coverage for property damage (UMPD) is optional in Montana. If you did not purchase UMPD, you cannot recover for damage to your vehicle under the UM claim. Your collision or comprehensive coverage would apply, but with your deductible.

Expert Tips

• Review your policy's declarations page annually to confirm your UM limits and whether stacking is permitted or excluded.
• If you carry only the state minimum UM limits of $25,000/$50,000, consider increasing them, medical costs from a serious crash can far exceed $25,000.
• If you live in a household with multiple vehicles and multiple policies, consult your agent about whether each policy's UM coverage can be stacked across policies.
• Montana law does not require underinsured motorist (UIM) coverage, but it is strongly recommended, it covers the gap when the at-fault driver has insurance but not enough.

Mistakes to Avoid

• Assuming UM coverage automatically applies for property damage. UMPD is optional, you may need collision coverage to repair your car unless you bought UMPD.
• Waiting more than 24 hours to report a hit-and-run to police, your insurer may deny the claim without a timely police report.
• Signing a UM waiver without understanding the consequences. If you reject UM coverage, you lose access to this protection entirely.
• Failing to document all medical visits, lost workdays, and out-of-pocket expenses, your UM claim's value depends on your records.

Pros and Cons

• ✅ Pros: Covers injuries when the at-fault driver has no insurance; pays for lost wages and pain and suffering; stacking can increase available limits; covers hit-and-run accidents.
• 👎 Cons: Optional property damage coverage (UMPD); stacking may be prohibited by policy language; state minimum limits ($25k) may be too low for serious injuries; requires a police report for hit-and-run claims.

Bottom Line

Montana's uninsured motorist coverage is a mandatory-in-offer but optional-to-accept form of protection that most drivers should carry. With an uninsured driver rate near 11%, the risk of being hit by someone without coverage is real.

Stacking provisions can increase your protection significantly, but the state's minimum limits are low enough that anyone with significant assets or medical risk should consider higher limits, and a to cover the gap. ✅ Recommended for: All Montana drivers who want to protect their family's health and finances. ❌ Not recommended when: You have minimal assets and low medical risk and prefer a very low premium, but the trade-off is real exposure.