Yes, you can marry your first cousin once removed in most of the United States. A small number of states prohibit the marriage under statutes that ban unions between anyone “nearer of kin than second cousins,” and in those states the marriage is void from the start. Everywhere else, the relationship is not on the list of prohibited degrees, and you can apply for a marriage license like any other couple.
What a First Cousin Once Removed Actually Is
A first cousin once removed sits one generation away from you on the family tree. The label works in both directions: your parent’s first cousin is your first cousin once removed, and your first cousin’s child is also your first cousin once removed. The “once removed” part always means a one-generation gap.
Genetically, first cousins once removed share about 6.9% of their DNA on average, with a range of roughly 3% to 12%. That is about half of what full first cousins share, which averages around 14.4%.123andMe. Average Percent DNA Shared Between Relatives That number matters because state marriage restrictions are built around how closely two people are biologically related.
Which States Allow It and Which Don’t
About half of all U.S. states ban marriage between first cousins. Far fewer extend the ban to first cousins once removed. In most states, the prohibited-marriage statute names the specific relationships it covers (parent and child, siblings, uncle and niece, and so on), and first cousins once removed simply do not appear on the list.
A handful of states use broader language that reaches this relationship. These statutes typically prohibit marriage between anyone “nearer of kin than second cousins.” Second cousins share a great-grandparent and are more distant on the family tree. A first cousin once removed is closer than that, so the relationship falls inside the prohibition. If your state uses this kind of language, the marriage is not allowed.
Check your own state’s statute before you file anything. A county clerk in a restrictive state will deny the application if you disclose the relationship, and hiding it creates a separate set of problems.
What Happens if Your State Prohibits It
In states that ban this union, the marriage is void. A void marriage is treated as though it never existed. You get none of the legal protections that come with marriage: no spousal inheritance, no medical decision-making authority, no joint tax filing, no community-property rights. A court does not have to annul a void marriage, because there is nothing to annul. If the issue surfaces years later in a property dispute or an estate proceeding, a court can declare the marriage was never valid.
Some states classify marriages within the prohibited degrees as incestuous, which can carry criminal penalties. Enforcement against couples is rare, but a clerk who knowingly issues a license to an ineligible couple can face misdemeanor charges. Verify eligibility before you apply.
Can You Cross State Lines to Marry?
Couples in a prohibitive state sometimes think about traveling to a permissive state, marrying there, and returning home. This can work, but it carries real risk.
Several states have marriage-evasion statutes that void a marriage performed elsewhere if the couple left specifically to dodge a local prohibition and then came back to live in the prohibiting state. The reasoning is simple: if your home state says the marriage is void, stepping out of the state for a weekend does not fix that. Not every state has an evasion statute, and courts do not always apply them, but couples relying on this workaround should understand they may come home to a marriage their state refuses to recognize. The U.S. Constitution’s Full Faith and Credit Clause requires states to respect judgments from other states, but marriage is not always treated the same way as a court judgment.2Constitution Center. Article IV, Section 1 – Full Faith and Credit Clause
Immigration Petitions Based on the Marriage
If one partner is not a U.S. citizen and you plan to file a visa petition or green card application, the marriage’s validity matters at the federal level too. Federal immigration authorities apply state law rather than a single national standard. USCIS evaluates the marriage against the law of the state where the couple lives or intends to live.
A marriage between first cousins once removed performed legally abroad or in a permissive U.S. state can still be rejected for immigration purposes if the couple’s home state considers it void. The Department of State’s Foreign Affairs Manual acknowledges this directly: “a marriage that is void under state law, such as a relative marriage, may be recognized as valid by the state of intended immigration,” with the outcome turning on the specific state involved.3U.S. Department of State. 9 FAM 102.8 Family-Based Relationships Confirm legality in your state of residence before investing in an immigration application built on this marriage.
Genetic Risk for Children
The genetic overlap between first cousins once removed is modest but not zero. At an average of 6.9% shared DNA, the couple is more closely related than second cousins (about 3%) and considerably less related than first cousins (about 14.4%).123andMe. Average Percent DNA Shared Between Relatives
Clinical genetics defines a consanguineous union as one between second cousins or closer, which includes first cousins once removed. For first cousins, research puts the added risk of birth defects at roughly double the population baseline, about 5% compared to 2.5% in the general population. For first cousins once removed the risk is lower because the genetic overlap is smaller. One genetics-education resource puts the chance of a birth defect at roughly 1 in 17 for first-cousin-once-removed couples, compared to about 1 in 33 for unrelated couples. Medical researchers have noted that among non-inbred populations, the risk for couples more distantly related than first cousins may approach that of unrelated couples.4National Institutes of Health. Consanguineous Marriages – Preconception Consultation in Primary Health Care Settings
Genetic counseling before having children is a reasonable step for any consanguineous couple. A counselor can review both partners’ family medical histories, flag known hereditary conditions, and run carrier screening for recessive disorders. It is especially worthwhile if both partners come from an extended family with a history of specific genetic conditions.
Getting the Marriage License
Once you have confirmed the marriage is legal where you live, the licensing process is the same as for any other couple. Both partners generally need to appear in person at the county clerk’s office with government-issued photo ID and basic personal information, including Social Security numbers and parents’ names and birthplaces.
If the application asks about your relationship or degree of kinship, answer honestly. Clerks use that information to verify the marriage is not prohibited. Misrepresenting the relationship is a separate offense in many jurisdictions and can void the marriage later even when the union itself would have been perfectly legal.
License fees generally run from about $25 to $90 depending on the jurisdiction. Many states impose a waiting period of one to three days between license issuance and the ceremony, and most licenses expire within 60 to 90 days if unused. Miss the window and you start over with a new application and a new fee.