In Oregon, it is illegal for first cousins (or closer relatives) to marry, with very limited exceptions. The state treats such a union as a “void” marriage, meaning it is not legally recognized even if a ceremony is performed.
What Oregon law specifically bans
Oregon Revised Statutes § 106.020 prohibits any marriage where the parties are first cousins or “any nearer of kin,” including parents, siblings, half‑siblings, aunts, uncles, grandparents, nieces, and nephews, whether related by blood, half‑blood, or adoption. Marriages that fall into this category are “absolutely void,” so they can be declared invalid at any time and do not create legal spousal rights.
The adoption‑cousin exception
There is one narrow exception: if two people are first cousins only by adoption (not by blood), their marriage is not prohibited or void under Oregon law. This exception recognizes that no biological‑family‑line restriction applies, but it still requires that neither party is married to someone else and that both meet general marriage‑age requirements.
What is allowed
Oregon law allows people to marry second cousins or more distant relatives, as long as they are otherwise eligible (age 18 or 17 with proper consent, not married to another person, and not within the prohibited “closer‑kin” circle).
Counties and officiants will check relationship‑eligibility before issuing a marriage license, and outright cousin‑cousin (first‑degree) petitions are typically denied there.
Practical takeaway
If you are related as first cousins, an Oregon marriage between you is not legally valid, and local authorities can refuse to issue a license or later declare the union void.
If you are unsure of how a family relationship is classified (for example, half‑cousin, step‑ or adopted‑cousin), consulting a family‑law attorney or a county clerk helps ensure you stay within Oregon’s marriage‑eligibility rules.
SOURCES :
- https://getordained.org/state-marriage-laws/oregon
- https://en.wikipedia.org/wiki/Cousin_marriage_law_in_the_United_States
