Montana Divorce Residency Requirements: The 90-Day Rule Explained

Before you can file for dissolution of marriage in Montana, the court must have jurisdiction over your case. That starts with residency. Montana has one of the shorter residency thresholds in the country, but there are multiple time periods at play that frequently confuse pro se filers.

The 90-Day Domicile Rule

Under MCA § 40-4-104(1)(a), at least one spouse must have been domiciled in Montana for a minimum of 90 consecutive days immediately preceding the filing of the petition. This is a strict statutory floor — no exceptions exist for shorter residencies, and the court is legally required to dismiss any petition filed before this period is complete.

"Domiciled" means more than just being physically present. It means Montana is your permanent home — you live here, work here, have a Montana driver's license, vote here. Temporary stays, vacations, or business trips don't count.

Military exception: Service members stationed in Montana by military orders also satisfy the domicile requirement, even if their legal home of record is another state.

The 180-Day Separation Period

This is the rule most people confuse with the residency requirement. Under MCA § 40-4-107, one of the two grounds for proving irretrievable breakdown is that the spouses have lived "separate and apart" for more than 180 continuous days before filing.

The 180-day period is about proving your grounds for dissolution — it's an alternative to claiming serious marital discord. You don't need to satisfy both. If you can certify under oath that serious marital discord exists and reconciliation isn't possible, the 180-day separation isn't required at all.

And "separate and apart" doesn't necessarily mean separate addresses. Courts have accepted that spouses living under the same roof can meet this standard if they've ceased marital and sexual relations and maintain distinct financial lives.

The 6-Month Child Residency Rule (UCCJEA)

If you have minor children, a third time period applies. Under the Uniform Child Custody Jurisdiction and Enforcement Act (MCA § 40-4-211), the children must have lived in Montana for at least six consecutive months for the court to have jurisdiction over custody and parenting orders.

This is separate from the 90-day adult residency rule. You might meet the 90-day threshold and be able to file for the dissolution itself, but if your children haven't been in Montana for six months, the court cannot issue binding orders about custody, parenting time, or child support. Emergency physical safety exceptions exist, but they require proving an immediate risk.

County Venue Rules

Once you've established statewide residency, you need to pick the right county. Under MCA § 25-2-118(3), you must file in a county where either you or your spouse has lived for the 90 days preceding the filing.

If you live in different Montana counties, you can choose either one. Some tactical considerations:

• Urban vs. rural: Yellowstone, Missoula, and Gallatin counties often have longer backlogs. A rural county may process your case faster.
• Children's location: Filing in the county where your children live makes future parenting plan modifications easier.
• Local rules: Some judicial districts use standing masters for initial family law matters, while others assign cases directly to District Court judges.

Quick Reference

The Montana Divorce Filing Process Guide includes a residency eligibility worksheet and county venue guide to help you confirm jurisdiction before you start filling out forms.

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