No. South Dakota does not recognize common law marriage formed within the state. Since July 1, 1959, state law has required every marriage to be solemnized by an authorized officiant and recorded with the county register of deeds. Living together, sharing a last name, or calling each other husband and wife does not create a legal marriage in South Dakota, no matter how many years have passed. The one exception: if you formed a valid common law marriage in another state that allows them, South Dakota will treat you as married.
The 1959 Cutoff and What the Statute Requires
South Dakota defines marriage as a personal relation arising out of a civil contract, but the statute is explicit that consent alone is not enough. Consent “must be followed by a solemnization.” A separate provision says marriages must be solemnized, authenticated, and recorded, while preserving any lawful marriage “contracted before July 1, 1959.”1Justia Law. South Dakota Codified Laws Title 25 Chapter 01 – Section: 25-1-29 That language grandfathered the common law marriages that existed when the rule changed. For every relationship formed since, a ceremony and a license are the only route to legal recognition.
The license itself is not onerous. It costs $40, there is no waiting period, no blood test is required, and the ceremony must take place within 90 days of purchase.2South Dakota Department of Health. Marriage Requirements
Common Law Marriages From Other States
If you established a valid common law marriage in a state that allows them and then moved to South Dakota, your marriage remains legally valid here. A marriage that was valid where it was formed is generally treated as valid in every other state, and South Dakota follows that principle.
A small group of states still permit new common law marriages, including Colorado, Iowa, Kansas, Montana, South Carolina, Texas, and Utah, with Rhode Island and Oklahoma recognizing them through case law. New Hampshire recognizes common law relationships only for inheritance after one partner dies. Several additional states, like South Dakota, grandfather common law marriages formed before a specific cutoff. If your relationship meets the originating state’s rules, South Dakota treats it the same as any licensed marriage.
How an Out-of-State Common Law Marriage Gets Proven
When the question comes up in a South Dakota court, usually during a separation or after a death, the issue is whether the marriage was validly formed under the law of the state where it originated. Those states vary, but most require three things: both partners had the legal capacity to marry, both intended to be married, and the couple held themselves out publicly as married.
The “holding out” piece is where fights happen. Courts look for concrete evidence:
- A shared last name adopted by one or both partners.
- Joint federal tax returns filed as married.
- Beneficiary designations naming the partner on insurance, retirement accounts, or similar documents.
- Joint bank accounts, jointly titled property, or co-signed loans.
- Statements from friends, family, and neighbors who understood the couple to be married.
Disputes usually arise when one partner denies the marriage ever existed, often to avoid property division or support. Courts weigh everything together. A couple with joint tax returns, years of introducing each other as spouses, and a jointly owned home has a much stronger case than one with only a shared address.
A Valid Common Law Marriage Still Needs a Divorce
This surprises people. Once a common law marriage is legally established, it ends only through a formal court-ordered divorce. Moving apart does not undo it. Dropping the shared last name does not undo it. The dissolution process is identical to ending a ceremonial marriage, with the same property division, potential spousal support, and custody determinations.
If your common law marriage was formed in another state and you now live in South Dakota, you file for divorce in South Dakota’s circuit courts like any other married couple. The absence of a marriage license does not change the procedure.
Social Security and Federal Benefits
The Social Security Administration recognizes common law marriages for spousal and survivor benefits as long as the marriage was valid under the law of the state where it was formed. A common law marriage established in Kansas still counts after you move to South Dakota.
Proving it to the SSA requires signed statements. If both spouses are living, the SSA wants signed statements from both partners plus statements from two blood relatives. If one spouse has died, the surviving spouse provides a signed statement along with statements from two blood relatives of the deceased. The statements should explain why the signer believes the marriage existed. If blood relatives are unavailable, statements from other people can substitute.3Social Security Administration. 20 CFR 404.726 – Evidence of Common-Law Marriage
Federal employee benefits work similarly. The Office of Personnel Management lets federal employees enroll a common law spouse in the Federal Employees Health Benefits program, but requires either a court order recognizing the marriage or a signed declaration backed by documents such as the first page of a joint tax return or proof of shared finances and residency.4U.S. Office of Personnel Management. Family Member Eligibility Fact Sheet – Common Law Spouse Private employers set their own rules and documentation requirements vary.
What’s at Stake for Inheritance
If South Dakota recognizes your out-of-state common law marriage, you have the same inheritance rights as any legally married spouse. Under state intestacy law, a surviving spouse inherits the entire estate when the deceased had no descendants or when all descendants are also the surviving spouse’s children. Where descendants from outside the marriage exist, the surviving spouse receives the first $100,000 plus half the remaining estate. Surviving spouses also get a homestead allowance and exempt property that take priority over creditor claims.5South Dakota Legislature. South Dakota Codified Laws 29A-2 – Section: 29A-2-402
If your relationship is not recognized as a marriage, none of that applies. An unmarried partner has no automatic inheritance rights, no homestead allowance, and no elective share. Everything passes under the deceased partner’s will, or if there is no will, to blood relatives. Couples who assume decades of cohabitation gave them spousal rights can end up with nothing.
Protecting an Unmarried Relationship in South Dakota
South Dakota has no statute defining the rights of unmarried cohabiting partners. If you separate without a marriage and without a written agreement, dividing shared property means a court process with asset valuations, analysis of each partner’s contributions, and testimony about how the household was run. The results are unpredictable.
A cohabitation agreement functions much like a prenuptial agreement. It lets you define how household expenses are split, who owns what, what happens to shared assets if you separate, and how debts are handled. Provisions about children and support can be included, though courts retain authority to override them based on the child’s best interests. Partners who co-own a business should also have a buy-sell agreement.
Beyond a cohabitation agreement, unmarried couples should take additional steps to approximate what marriage provides automatically:
- Draft wills and name your partner as beneficiary on retirement accounts and life insurance. Without this, intestacy law passes nothing to your partner.
- Sign healthcare directives and powers of attorney. Without marriage, your partner has no automatic right to make medical or financial decisions in an emergency.
- Jointly title property. If you buy a home or vehicle together, both names belong on the title; otherwise the titled owner holds the legal claim.
These documents do not replicate every benefit of marriage, especially around tax filing, Social Security, and employer benefits. For couples who want the full set of legal protections in South Dakota, obtaining a marriage license and holding a ceremony is the most direct path: $40, no waiting period.2South Dakota Department of Health. Marriage Requirements