Marrying your cousin in Idaho is only illegal if the cousin is your first cousin—meaning you share a set of grandparents. According to Idaho law, specifically Idaho Code § 32-206, “All marriages between first cousins are prohibited”. This prohibition is clear and absolute; there are no exceptions or special circumstances under which first cousins may legally marry in Idaho.
However, the law does not prohibit marriage to more distant relatives such as second cousins (those with whom you share great-grandparents, not grandparents), or third cousins and beyond. Marriages between second cousins and more distant relatives are legal in Idaho and most other states.
Additionally, Idaho law prohibits other close family marriages, including between parents and children, siblings, and aunts/uncles with nieces/nephews, as these are considered incestuous and are void from the beginning.
Summary Table
| Relationship Type | Legal to Marry in Idaho? | Notes |
|---|---|---|
| First cousins | No | Prohibited by Idaho law |
| Second cousins | Yes | Legal in Idaho and most states |
| Third cousins & beyond | Yes | Legal in Idaho and most states |
| Parents/children | No | Prohibited (incestuous, void) |
| Siblings | No | Prohibited (incestuous, void) |
| Aunts/uncles/nephews/nieces | No | Prohibited (incestuous, void) |
You cannot legally marry your first cousin in Idaho. Marriages between second cousins and more distant relatives are allowed. Marriages between closer relatives (parents, children, siblings, aunts/uncles with nieces/nephews) are also prohibited.
Sources
[1] https://en.wikipedia.org/wiki/Cousin_marriage_law_in_the_United_States
[2] https://legislature.idaho.gov/statutesrules/idstat/title32/t32ch2/sect32-206/
[3] https://1043wowcountry.com/cousin-wedding-idaho-2023/
[4] https://legislature.idaho.gov/statutesrules/idstat/title32/t32ch2/
[5] https://mix106radio.com/marrying-cousin-legal-idaho-2022/
