NO, South Dakota does not currently allow couples to form new common law marriages. You cannot create a common law marriage in South Dakota today by living together or holding yourselves out as spouses.
However, South Dakota law includes an important grandfather exception, and it also respects marriages formed elsewhere. Understanding these distinctions matters, especially for inheritance, divorce, or survivor rights.
The Legal Rule in South Dakota
South Dakota follows a formal approach to marriage. For modern couples, marriage exists only when the legal steps are properly completed through the county.
To be legally married in South Dakota today, a couple must:
- Obtain a marriage license from the Register of Deeds office
- Meet statutory eligibility requirements
- Have the marriage solemnized by an authorized officiant
Without these steps, the relationship is legally considered unmarried, regardless of how long the couple has lived together.
No New Common Law Marriages Allowed
South Dakota law does not permit new common law marriages to be formed.
That means:
- Living together does not create marriage
- Calling each other husband and wife does not create marriage
- Sharing finances or raising children does not create marriage
For most modern couples, there is only one path to marriage in South Dakota: a valid marriage license issued by the county.
The Pre-1959 Grandfather Clause
South Dakota recognizes a narrow historical exception.
Common law marriages that were fully established before January 1, 1959, are still legally valid in South Dakota. This is known as the grandfather clause.
To qualify under this exception, the couple must have met traditional common law requirements before 1959, including:
- A mutual agreement to be married
- Cohabitation as spouses
- Holding themselves out publicly as married
These cases are extremely rare today and usually appear only in estate or inheritance disputes involving elderly estates.
Any relationship that began after January 1, 1959 cannot qualify as a South Dakota common law marriage.
Recognition of Out-of-State Common Law Marriages
Although South Dakota does not allow new common law marriages to form, it will recognize a valid common law marriage created in another state.
Under the Full Faith and Credit Clause of the U.S. Constitution:
- If a couple formed a valid common law marriage in a state where it is legal (such as Colorado or Iowa),
- And later moved to South Dakota,
South Dakota will generally recognize that marriage as valid.
The key requirement is that the marriage must have been legally valid in the state where it was formed.
South Dakota does not create these marriages—but it respects them once they already exist.
Long-Term Couples Are Still Unmarried Under South Dakota Law
South Dakota draws a clear line between:
- Committed relationships, and
- Legal marriages
A couple may:
- Live together for decades
- Own property jointly
- Share finances
- Raise children
- Be socially viewed as spouses
And still have no spousal rights under South Dakota law unless they formally married or qualify under the narrow pre-1959 exception.
Commitment alone does not create marital status.
What Happens If Unmarried Couples Separate?
Because common law marriage is not available for modern relationships, separation between unmarried partners is not a divorce.
Property
- Property belongs to whoever owns it or paid for it
- Joint property is divided based on ownership interests
- Courts do not apply marital property rules
Spousal Support
- Alimony applies only to legal marriages
- Unmarried partners generally have no right to spousal support
Children
- Child custody and child support are handled separately
- Parental obligations exist regardless of marriage
Death and Inheritance Risks
This is where incorrect assumptions cause the most harm.
If one partner dies without a will:
- The surviving unmarried partner does not automatically inherit
- Assets pass to legal heirs under South Dakota intestacy law
Unless a valid pre-1959 common law marriage or a recognized out-of-state common law marriage can be proven, long-term partners may receive nothing.
Why South Dakota Uses This System
South Dakota prioritizes clarity and legal certainty. Requiring formal marriage:
- Reduces disputes
- Prevents inheritance conflicts
- Avoids forcing courts to reconstruct relationships years later
The law favors clear legal acts over implied marital status.
Final Takeaway
South Dakota does not allow new common law marriages to be formed today. Only marriages that:
- Were established before January 1, 1959, or
- Were validly created in another state that recognizes common law marriage
will be honored.
For nearly all modern couples, a formal marriage license obtained through the county is the only way to be legally married in South Dakota. Living together—even for decades—does not create marriage rights. When marriage is not part of the plan, careful legal and estate planning is essential to avoid painful surprises later.
