Cousin Marriage Laws in the United States: A State-by-State Guide 2026
First, what counts as a cousin?
The word "cousin" covers several different relationships, and the law treats them differently.
First cousins share a set of grandparents. Your aunt's or uncle's child is your first cousin.
Double first cousins are first cousins through both sides of the family, for example when two brothers marry two sisters and have children. They share more DNA than ordinary first cousins.
First cousins once removed are separated by one generation. Your first cousin's child is your first cousin once removed.
Second cousins share great-grandparents, not grandparents.
Most of the legal debate is about first cousins. Second cousins can marry in every state, and most states put no limit on first cousins once removed (a few do, covered below).
The big picture: no federal law, 50 different rules
Marriage in the US is regulated at the state level. The federal government does not set the list of relatives you may or may not marry. That is why you can drive across a state line and find that a marriage legal in one place is illegal in the next.
Counts differ slightly depending on the source, because some lists treat conditional states differently. Roughly:
About 19 states plus Washington, DC allow first cousins to marry with no special conditions.
Six or seven states allow it only under certain conditions, such as age or genetic counseling.
About 24 to 25 states ban it outright.
Treat any single headline number with caution and confirm the current rule with your state's statute or county clerk before making plans.
States where first cousin marriage is legal
The following states and DC generally allow first cousins to marry without conditions:
Region | States |
Northeast | Connecticut, Massachusetts, New Jersey, New York, Rhode Island, Vermont |
Mid-Atlantic and South | Alabama, Florida, Georgia, Maryland, North Carolina, South Carolina, Tennessee, Virginia, District of Columbia |
West and Pacific | Alaska, California, Colorado, Hawaii, New Mexico |
A few details are worth knowing:
North Carolina allows first cousins to marry but prohibits double first cousins.
Tennessee allows first cousins but does not allow marriage to a first cousin once removed.
Florida has seen repeated attempts to change the law. A bill to ban first cousin marriage failed in the state Senate in March 2026, and its sponsor said he expects the issue to return. If you live in Florida, check for new legislation before you rely on this article.
Some older lists, including ones still circulating online, show different states as legal or illegal. Laws have changed over time, so older articles are not always reliable.
States with conditions
Seven states take a middle path. They do not flatly ban first cousin marriage, but they only allow it when certain conditions are met.
State | Condition for first cousins |
Arizona | Both partners are 65 or older, or one partner cannot have children (a court may need to confirm this) |
Illinois | Both partners are 50 or older, or one partner cannot have children |
Indiana | Both partners are at least 65 |
Maine | The couple gets a physician's certificate showing they have received genetic counseling |
Minnesota | Generally prohibited, except for marriages permitted by the established customs of aboriginal cultures (read as Native American or Indigenous communities) |
Utah | Both are 65 or older, or both are 55 or older and one cannot have children |
Wisconsin | The woman is 55 or older, or one partner cannot have children |
The age-based rules rest on a simple idea: the main worry with cousin marriage is the possibility of children, so the law relaxes when that possibility is gone or reduced. Whether such rules are fair, or whether they require couples to disclose private medical facts, is debate legal scholars still have.
States where first cousin marriage is banned
The remaining states prohibit marriage between first cousins. These include Arkansas, Delaware, Idaho, Iowa, Kansas, Kentucky, Louisiana, Michigan, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Dakota, Texas, Washington, West Virginia and Wyoming.
In these states, a marriage between first cousins is usually treated as void, meaning the law treats it as if it never validly existed. That can affect things like inheritance, spousal benefits, and health insurance coverage.
A handful of these states go further and make it a criminal offense. Texas, Oklahoma, North Dakota, South Dakota and Nevada are among those commonly listed, along with Arizona, Utah and Wisconsin, which can penalize marriages that fall outside their conditions. Prosecutions over adult cousin marriage are rare in practice, but the possibility exists on paper.
Some states also limit marriage between first cousins once removed. Kentucky, Nevada, Ohio, Tennessee, Utah, Washington and Wisconsin are the ones usually named.
Which states have the most cousin marriages?
This is a question many readers ask, and the honest answer is that nobody knows precisely. The US Census and state health departments do not track whether married couples are related, so no reliable state-by-state count exists. Researchers who have studied the subject describe the data as sparse, and the figure most often cited puts cousin marriage at a small fraction of one percent of marriages nationwide.
What we can say is more limited:
Cousin marriage can only happen in significant numbers where it is legal, so the states in the first table are where the question arises most often.
Populous states that allow it, such as California, New York, Florida, Georgia, Virginia and North Carolina, will naturally have more such couples in raw numbers than small states, simply because they have more marriages overall.
Cousin marriage is more common in some immigrant communities with long-standing traditions of marrying within the extended family, and in some rural or tightly knit communities. This is a pattern, not a count, and it should not be turned into a claim about any particular group or place.
If you see a website claiming exact numbers for a specific state, ask where the data came from. Most of the time there is no source.
Why do some states allow it and others ban it?
Cousin marriage was never a problem under English common law, which is the legal tradition most US states inherited. Many states simply never passed a ban. Bans appeared mostly in the 1800s, driven by changing social attitudes and early ideas about heredity, and spread through the Midwest and West. In the early twentieth century, some bans were tied to the eugenics movement, an effort now widely discredited.
Today the arguments on each side look like this:
For bans: supporters point to genetic risk, to concerns about family pressure in some communities, and to public sentiment against the practice.
Against bans: opponents note that the added genetic risk is modest, that many countries and cultures treat cousin marriage as normal, and that the state should have a strong reason before telling adults whom they may marry.
People on both sides tend to cite the same science, which brings us to the next section.
What the science says
The best-known US review is a 2002 paper by genetic counselors in the Journal of Genetic Counseling. It found that children of first cousins have a somewhat higher chance of serious birth defects or genetic conditions than children of unrelated parents. The commonly quoted figures are about 4 to 6 percent for first cousins, compared with roughly 3 percent in the general population. That is an increase of about 2 to 3 percentage points.
In other words, the risk is real but small. The vast majority of first cousin couples have healthy children. The risk rises if the same family has married within itself over several generations, and it is higher for double first cousins. Genetic counseling before pregnancy lets couples look at their own family history, which is why Maine builds it into the law.
Incest laws are a separate thing
Cousin marriage and incest are often mixed up, but the law treats them as different subjects.
Marriage laws decide who can get a marriage license and whether a marriage is valid.
Incest laws are criminal laws that target sexual conduct, and sometimes marriage itself, between close relatives.
Every state restricts marriage between certain close relatives, such as parents and children or siblings. Marriage between aunts or uncles and nieces or nephews is also generally prohibited, although specific statutory exceptions can complicate the rules. Rhode Island, for example, has a longstanding provision (§ 15-1-4) creating an exception to certain marriage restrictions for marriages solemnized among Jewish people when the degree of kinship is permitted by their religious law. This exception concerns marriage law and should not be confused with a blanket exemption from criminal incest laws.
Criminal laws also vary by state. New Jersey and Rhode Island are often cited as states that do not generally criminalize consensual sexual relations between adult relatives under their incest statutes, but this does not mean that marriage between those relatives is necessarily legal. Other criminal laws and restrictions may still apply.
First-cousin relationships are another distinct issue. In states where first-cousin marriage is legal, a consensual relationship between adult first cousins is not automatically a crime of incest. In states that restrict such marriages, the treatment of sexual relations varies according to the applicable statutes.
Sexual conduct involving a child or a minor may constitute a serious crime, depending on the circumstances and applicable laws, regardless of the family relationship. Anyone experiencing abuse can contact the National Child Abuse Hotline at 1-800-422-4453 or the National Sexual Assault Hotline at 1-800-656-4673.
What if you marry in one state and live in another?
The general rule in US law is that a marriage valid where it was performed is valid everywhere. Cousins from a state that bans cousin marriage sometimes travel to a state where it is legal, marry there, and return home.
How this plays out depends on the home state. Some states recognize the marriage. Others have laws that refuse to recognize marriages made elsewhere to avoid the home state's rules, and a few can penalize the couple. The result is not uniform, and courts in different states have not always agreed.
A similar question comes up for immigrant couples who married abroad, where cousin marriage is common. Immigration authorities generally look at whether the marriage was valid where it took place, and then at whether it conflicts with the public policy of the state where the couple lives. If this applies to you, speak with an immigration attorney.
Practical tips before you apply for a license
Read your state's current statute. Search for your state's marriage law online or call the county clerk's office. Laws get amended.
Ask about local requirements. Conditional states like Maine, Arizona and Illinois require paperwork or proof of age.
Consider genetic counseling if you plan to have children, whether or not your state requires it.
Speak with a family law attorney if you are moving between states, have immigration questions, or are in a state with criminal penalties.
Keep copies of your marriage certificate and related records, since you may need to prove the marriage's validity to a new state, insurer or agency.
Frequently asked questions
Is it legal to marry your first cousin in the US?
It depends on the state. Roughly 19 states and DC allow it freely, about 7 allow it under conditions, and the rest ban it.
Is marrying a second cousin legal?
Yes, in every state.
Can I be arrested for marrying my cousin?
In a few states with bans, it can be a criminal offense, though prosecution of consenting adults is uncommon. Legal advice for your state is the safe route.
Will my marriage be recognized if I marry in a state where it is legal?
Often yes, but not always. Some states refuse to recognize such marriages. Check the rules in the state where you plan to live.
Are children of cousin marriages considered legitimate?
Generally yes. Most states have laws protecting the legal status of children even when a marriage is later found void.
Do states keep statistics on cousin marriage?
No. There is no reliable national or state-level count.
Sources and further reading
This article draws on current reporting and legal summaries, including the National Conference of State Legislatures' marriage-law resources, Wikipedia's state-law tables for cousin marriage and incest, reporting on Florida's 2026 bill, and the 2002 genetic counseling review by Bennett and colleagues. State statutes change, so use your state legislature's website for the final word.
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