By Neta, founder of SortMyDivorce · Published · Updated
90 days in Montana before filing, then 21 days after your spouse is served with the petition. Montana does grant legal separation.
Montana calls it 'dissolution of marriage' rather than divorce, and its property rules are unusual among states — preparing well here means understanding how broadly a Montana court can look at what gets divided.
| Residency requirement | At least one spouse must have been domiciled in Montana (or stationed there on military orders) for 90 days immediately before filing. |
|---|---|
| Grounds | No-fault only — the marriage must be 'irretrievably broken,' shown by living separate and apart for more than 180 days OR by serious marital discord with no reasonable prospect of reconciliation. |
| Waiting period | The court cannot enter a final decree until at least 21 days after the respondent is served with the petition. |
| Legal separation | Montana does grant legal separation. It settles the same questions a divorce settles — support, parenting and, depending on the case, property — but leaves the marriage in place, so neither spouse can remarry without a divorce. |
| If you were never married | Montana is one of the few states that still creates common-law marriage. If you met its test, you are legally married — and ending the relationship takes a divorce, with the same property rules as any other marriage. |
| Where you file | The Petition for Dissolution of Marriage is filed with the Clerk of District Court in the county where either spouse resides. |
| Filing fee | Payable when you file your opening divorce document. Set locally by the county, not as one statewide rate. A fee waiver is available if you cannot afford it (Statement of Inability to Pay Court Costs and Fees). Filing fees are set by the court and change without notice: check the current schedule on the court's own website before you file, and ask about a fee waiver if the cost is a barrier. |
| Starting forms | MP-112 (Petition for Dissolution without Children) or MP-113 (with children) for an individual filing; MP-115 (Joint, no children) or MP-121 (Joint, with children) if both spouses agree, plus MP-400 (Summons) and MP-500 (Financial Disclosure and Proposed Property Distribution). |
| Simplified option | Yes — summary dissolution under MCA §40-4-130. There is no limit on how long you have been married, and having children does not automatically disqualify you: you can use it with children provided you have an agreed parenting plan and a support order in place. The asset and debt ceilings do apply. |
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Montana is an equitable apportionment state, but with a twist that surprises many people: unlike most equitable-distribution states, Montana law does not automatically wall off separate property (assets owned before the marriage, inheritances, gifts) from division. A court can consider all property owned by either spouse, however and whenever acquired, and apportion it equitably between them. In practice, courts still weigh the source of an asset heavily — property one spouse brought into the marriage or inherited individually is less likely to be split evenly than property built together — but it is not off the table by default the way it is in many other states. That makes the story you can tell about an asset's origin, and the paper trail behind it, genuinely important in Montana.
Dissolution petitions are filed in the District Court for the county where you or your spouse lives, since Montana does not have separate family courts. There is a residency requirement — generally you or your spouse must have lived in Montana for 90 days before filing. Montana is a no-fault state: the standard ground is that the marriage is 'irretrievably broken,' which can be shown by the parties living apart or by serious marital discord that a judge finds has undermined the marriage. Once a petition is filed and served, Montana law sets a mandatory 21-day waiting period before a decree of dissolution can be entered — a shorter wait than many states, but it still shapes how quickly even an agreed case can conclude.
Because Montana courts can look at property regardless of when or how it was acquired, documentation of an asset's origin matters more here than in states with a hard separate-property line. If you owned a house, retirement account, or business before the marriage, or received an inheritance or gift during it, gather the records that show that history: purchase documents, account statements from around the date of the marriage, inheritance or estate paperwork, and anything showing how the asset was (or wasn't) mixed with marital funds over time.
Beyond that, the general disclosure list applies: recent tax returns, pay statements, statements for every bank, investment, and retirement account, mortgage and property tax records, vehicle titles, and debt statements. If either spouse is self-employed or owns a business, business financials and tax filings will matter for both property division and any support calculation.
From the first letter you receive — whether from your spouse's attorney, a mediator, or the court — keep everything. In a case where the property pool can be argued to be broader than usual, the letters documenting who claimed what, and when, often become the reference point once negotiations get specific.
Montana uses 'parenting plans' rather than custody orders, and courts decide them based on the best interests of the child — factors like the child's relationship with each parent, adjustment to home and school, and each parent's willingness to support the other's relationship with the child. Montana courts and many local rules encourage parents to reach a parenting plan by agreement or mediation before a judge imposes one.
Child support follows the Montana Child Support Guidelines, which are calculated from both parents' incomes and the parenting schedule. As with most states, the guideline amount is a starting point that can be adjusted for specific circumstances a judge finds relevant.
Legal separation is available in Montana. It is a court proceeding, and in most respects it runs like a divorce: the court can settle support, parenting arrangements and, depending on the case, the division of property, and the resulting order binds both spouses.
What it does not do is end the marriage. People choose it for a range of reasons — health coverage, religious conviction, immigration status, or simply not being ready — and it leaves the door open to reconciling without starting over.
Two consequences follow. Neither spouse can remarry unless they later obtain a divorce, and modifying the order generally takes the court's approval rather than a private agreement between you. If you expect to divorce eventually, ask what converting the separation into a divorce involves here before you start.
Montana is unusual. Most states abolished common-law marriage; Montana did not. That means a couple who never had a ceremony may nonetheless be legally married, and may not realise it until they separate and one of them claims a share of the other's property.
The test is not simply living together for a period of years — that alone creates nothing anywhere. It generally requires that the couple agreed to be married, lived together as spouses afterwards, and held themselves out to others as married. Confirm the precise requirements here before assuming either way.
If you were common-law married, you are married: the state's property rules apply and ending it takes a divorce. If you were not, this state's family law offers unmarried partners very little — no property division and no spousal support between you, with claims left to contract and general legal principles. Children are the exception, since custody and child support are decided the same way whether or not the parents married.
1) Pull together the origin story for any asset you consider 'yours alone' — purchase records, pre-marriage statements, inheritance documents — since Montana's broader view of divisible property makes this evidence carry real weight. 2) Confirm your residency timeline meets the 90-day threshold before you plan a filing date. 3) Get at least one consultation with a Montana family law attorney, even if you intend to negotiate directly, so you understand how apportionment is likely to treat your specific property. 4) Build your full disclosure binder early, since Montana's District Courts still expect thorough financial disclosure even without a statewide standardized affidavit. 5) Track the 21-day clock once you file or are served — it's short enough that missing a step can cost real time, and long enough that it's worth planning around.
One spouse must have been domiciled in Montana for at least 90 days before filing. If neither of you meets this, you'll need to wait or file elsewhere.
Montana only recognizes no-fault dissolution. Your petition must state either that you've lived separate and apart for more than 180 days, or that there is serious marital discord with no reasonable prospect of reconciliation.
If you and your spouse agree on everything and meet the asset/debt limits, ask about Summary Dissolution (MCA 40-4-130). If you agree generally but don't qualify for summary dissolution, a Joint Petition (MP-115 or MP-121) skips formal service. Otherwise, file individually (MP-112 or MP-113).
Download the packet for your situation from courts.mt.gov, montanalawhelp.org, or a Court Help self-help law center — the same forms are free from all three sources.
File your Petition for Dissolution with the Clerk of District Court in the county where you or your spouse resides, along with the filing fee. File a Statement of Inability to Pay Court Costs and Fees at the same time if you need a waiver.
If you filed alone, your spouse must be formally served with the Summons (MP-400) and petition. They then have 21 days to file a verified response.
Both spouses complete a Financial Disclosure and Proposed Property Distribution (MP-500) so the court has an accurate picture of income, assets, and debts before dividing property or setting support.
The court cannot sign a final decree until at least 21 days after service. Once that period has passed and any parenting plan or property agreement is in order, file a Request for Hearing (MP-701) and a proposed Decree (MP-713) for the judge's signature.
Montana recognizes common-law marriage. If you meet the legal test for one, ending it legally requires this same court dissolution process — simply separating or moving out does not end the marriage.
Montana is an equitable apportionment state, and it is unusual among them: the law does not automatically wall off separate property. A court can consider everything either spouse owns, including assets brought into the marriage or inherited, and divide it in whatever way it finds equitable. Equitable means fair in the court's assessment, which is not the same as half each.
Not necessarily. Montana courts can consider all property owned by either spouse, including what was owned before the marriage or received as a gift or inheritance, and apportion it equitably. Courts generally still weigh an asset's source heavily, so documenting where property came from matters.
Montana generally requires 21 days from filing and service before a court can enter a decree of dissolution. This is shorter than many states, but it still affects how quickly a case — even an uncontested one — can be finalized.
Generally yes — Montana law requires that you or your spouse have lived in the state for 90 days before filing a dissolution petition. Confirm your specific situation with a Montana attorney or the District Court clerk in your county.
A legal separation in Montana settles much of what a divorce settles — support, parenting and, depending on the case, property — and the order binds both spouses. The difference is that it does not end the marriage, so neither spouse can remarry without later obtaining a divorce. People use it for health coverage, religious reasons, immigration status, or because they are not ready to divorce. Changing the order generally requires the court's approval.
Yes — Montana is one of the small number of states that still creates common-law marriage. It generally requires an agreement to be married, living together as spouses afterwards, and representing to others that you are married; simply living together for a number of years is not enough on its own. If the test is met you are legally married, the state's property rules apply, and ending the relationship requires a divorce. If it is not met, there is no property division or spousal support between you, though custody and child support apply regardless.
If you are in immediate danger, call 911. There is no statewide crisis line here that we could verify, so use the national one: contact the National Domestic Violence Hotline at 1-800-799-7233, or text START to 88788 if a call is not safe. For a mental health crisis, call or text 988.
Last reviewed August 2026. Researched and written by Neta, founder of SortMyDivorce. I am not a lawyer and this is not legal advice — laws, fees and forms change, so please confirm current details with the official sources above or a local family lawyer.
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