Yes — Ohio law bars marriages between first cousins; the statute limits lawful marriages to people “not nearer of kin than second cousins,” so first-cousin marriages cannot be legally performed in Ohio.
What the statute says
Ohio Revised Code § 3101.01 requires that persons who marry be “not nearer of kin than second cousins,” which means a marriage between first cousins is outside the class of permitted marriages under Ohio law.
Are first‑cousin marriages automatically void?
Because Ohio’s statutory rule restricts who “may be joined in marriage,” marriages that are closer than second cousins (including first cousins) cannot be lawfully entered into in Ohio; in practice a county probate court will not issue a marriage license to first cousins. Some legal summaries and state guides treat such unions as prohibited and therefore not recognized for purposes of licensure and state benefits.
What if the marriage was performed elsewhere?
Several sources note nuance: marriages validly performed in another jurisdiction sometimes raise recognition questions, and courts can treat out‑of‑state cousin marriages differently depending on the facts and applicable choice‑of‑law rules.
However, because Ohio’s statute conditions who “may be joined in marriage,” couples should assume Ohio will not permit or recognize a first‑cousin marriage performed out of state without getting local legal advice.
Criminal and other consequences
Ohio’s consanguinity statute focuses on marriage eligibility; related criminal provisions (where applicable) may address sexual relations between certain relatives, and some summaries state that se**al relations with a first cousin can trigger incest-related offenses under Ohio law — penalties and applicability depend on specific statutory sections and case law, so consult an attorney for a case‑specific assessment
SOURCES:
- https://rivercityomaha.com/2025/01/is-it-illegal-to-marry-your-cousin-in-ohio-heres-what-the-law-says/
- https://en.wikipedia.org/wiki/Cousin_marriage
