Yes, it is illegal to marry your first cousin in South Dakota. The state prohibits marriages between first cousins, along with other close relatives. South Dakota law specifically bans marriages between:
- Parents and children
- Brothers and sisters (including half-siblings)
- Uncles and nieces
- Aunts and nephews
- First cousins
- Stepfathers and stepdaughters
- Stepmothers and stepsons
This prohibition applies even if the marriage was legally performed in another state where first-cousin marriages are allowed. South Dakota does not recognize such marriages contracted outside the state.
However, it’s worth noting that marriages between more distant relatives, such as second cousins or first cousins once removed, are permitted in South Dakota.
The state’s stance on cousin marriage aligns with several other states in the region. Both North and South Dakota have similar laws prohibiting first-cousin marriages. These restrictions are part of broader regulations aimed at preventing consanguineous marriages, which are unions between closely related individuals.
Sources:
- https://findalawyerinsd.com/pages/areas-marriage
- https://www.cambridge.org/core/books/consanguinity-in-context/civil-legislation-on-consanguineous-and-affinal-marriage/9EF9055CE8B71B20968684C7810870DB
- https://us1033.com/kissing-cousins-in-north-dakota-can-you-marry-your-first/
- https://www.ellsworth.af.mil/Portals/146/21_%20Marriage%20pamphlet.pdf
