Bigamy is the act of marrying someone while you are still legally married to another person. Every U.S. state treats it as a crime, and the second marriage is automatically void from the moment it happens. The consequences reach well past the criminal case itself, touching property, inheritance, taxes, children, and immigration status.
What Counts as Bigamy
The elements are simple. A person goes through a marriage ceremony, or obtains a marriage license and registers a union, while a prior marriage is still legally intact. The first marriage hasn’t ended through divorce, annulment, or the death of the other spouse, so the person lacks the legal capacity to marry again.1Legal Information Institute. Bigamy The form of the second ceremony doesn’t change the analysis. Religious, civil, or foreign, it counts if a valid first marriage still existed when it took place.
Where states differ sharply is on the mental element. Some require prosecutors to prove the person knew they were still married. Others treat bigamy as strict liability, meaning the prosecution doesn’t need to show knowledge at all. In a strict-liability state, honestly believing your divorce was final will not, by itself, defeat the charge.
Criminal Penalties
Penalties vary widely. Roughly half of U.S. states classify bigamy as a felony; the rest treat it as a misdemeanor. Prison sentences range from a few months to as much as ten years at the extreme end, with fines running from a few hundred dollars up to six figures in certain jurisdictions. For a first offense without aggravating circumstances, actual sentences typically land somewhere between one and five years, often with part of that time suspended in favor of probation.
Prosecutions are relatively uncommon. Many cases surface only when a new marriage license application triggers a records check, or when a spouse discovers the situation and reports it. Prosecutors tend to prioritize cases involving fraud, such as marrying someone to access their finances or benefits, over cases that boil down to paperwork confusion after a stalled divorce.
Defenses
The Model Penal Code recognizes four defenses that many states have adopted in some form:
- A genuine belief that the prior spouse had died.
- Living apart from the prior spouse for five consecutive years with no reason to believe they were alive.
- Reasonable reliance on a court judgment of divorce or annulment that later turned out to be invalid, as long as the person didn’t know of the defect.
- A broader catch-all that the person reasonably believed they were legally free to remarry.
Not every state adopts all four, and the defendant usually carries the burden of proof. The common thread is reasonableness. A vague hope that the divorce “probably went through” won’t hold up. Courts look for concrete steps: pulling court records, consulting an attorney, or holding a final decree in hand. Being told by an ex that the divorce was done is risky ground, though some states allow reliance on it when the circumstances made that reliance reasonable.
Why the Second Marriage Is Void
A bigamous marriage is void ab initio. In the law’s eyes, it never existed.1Legal Information Institute. Bigamy That makes it different from a voidable marriage, which stays valid until a court cancels it. No court order is required to end a void marriage, because there is nothing to end.
The practical fallout is harder than the doctrine. The second spouse may have spent years building a life around what they believed was a valid marriage: joint accounts, a shared mortgage, children, joint tax returns. Void status pulls the legal footing out from under all of it at once.
Property, Inheritance, and the Putative Spouse
Because the second marriage doesn’t legally exist, the usual rules for dividing marital property don’t apply. Community property regimes, equitable distribution, and spousal support all depend on a valid marriage. Without one, the second spouse generally has no automatic claim to the other person’s bank accounts, retirement funds, or real estate.
Inheritance works the same way. A spouse in a void marriage cannot claim through intestacy, and cannot claim the elective share that most states guarantee a surviving spouse. The first, legally recognized spouse keeps those rights. A specific bequest in a will can still be honored, depending on the will’s language and the probate court’s reading of it.
About a dozen states, including California, Colorado, Illinois, Louisiana, Minnesota, Montana, and Texas, soften that outcome through the putative spouse doctrine. A putative spouse is someone who honestly believed the marriage was valid and had no reason to suspect otherwise. Where the doctrine applies, a court can divide property acquired during the relationship as though the marriage had been real, and may award spousal support. Putative rights don’t override those of the legal spouse from the first marriage; if both have claims to the same assets, the court divides equitably. The Social Security Administration follows state law on this point, treating a putative spouse as eligible for spousal or survivor benefits where the state recognizes the doctrine, and apportioning benefits when both a legal and putative spouse claim on the same worker’s record.2Social Security Administration. SSR 80-2 – Relationship, Validity of Marriage, Putative Marriage in Colorado
Taxes
Federal filing status depends on whether you were legally married under state law as of December 31 of the tax year.3Taxpayer Advocate Service. The Tax Ramifications of Tying the Knot If the marriage is void, the IRS doesn’t treat you as married, so neither Married Filing Jointly nor Married Filing Separately is available.4Office of the Law Revision Counsel. 26 USC 6013 – Joint Returns of Income Tax by Husband and Wife You’d file as Single, or Head of Household if you qualify.
Prior-year returns are the bigger problem. Joint returns filed during years when the marriage was void were technically incorrect, and open years may need to be amended, which can push liability in either direction. If the other spouse underreported income or claimed bogus deductions on joint returns you signed, the IRS can hold you responsible for the full balance. Innocent spouse relief, requested on IRS Form 8857, can protect you if you didn’t know about the errors and had no reason to suspect them.5Internal Revenue Service. Innocent Spouse Relief You generally have two years from the date of an IRS notice of taxes due to request it.
Children
Children born during a bigamous marriage are not penalized for their parents’ situation. The Uniform Parentage Act, adopted in some form by a majority of states, provides that a person is presumed to be the parent of a child born during a marriage “whether the marriage is or could be declared invalid.” The void status of the marriage doesn’t disturb the child’s legal relationship to either parent.
Even in states that haven’t adopted the UPA, the long-standing trend is to eliminate distinctions between children born inside and outside of marriage. Both parents remain obligated to support the child, and custody turns on the child’s best interests. A parent cannot avoid child support by arguing the marriage was void.
Immigration
For non-citizens, the stakes are high. Federal immigration law makes any immigrant coming to the United States to practice polygamy inadmissible.6Office of the Law Revision Counsel. 8 USC 1182 – Inadmissible Aliens Bigamy and polygamy are not identical, but immigration authorities treat a bigamous marriage as evidence of polygamous practice.
Naturalization applicants must show “good moral character” during the statutory period before filing. A bigamy conviction, or even an admission of practicing bigamy, can block that showing.7U.S. Citizenship and Immigration Services. Conditional Bars for Acts in Statutory Period Intentional bigamy generally triggers a five-year waiting period after the situation ends before a renewed application. Unintentional bigamy may not create a permanent bar, but the applicant typically has to dissolve the invalid marriage first. Form N-400 specifically asks whether the applicant has ever been married to more than one person at the same time. Lawful permanent residents who practice polygamy after obtaining status can face deportation, so anyone in that position should get an immigration attorney involved immediately.
Getting a Court Declaration of Nullity
A bigamous marriage is void by operation of law, but a court order confirming that status is still worth having. A declaration of nullity creates a formal record that the marriage never existed, which matters for name and Social Security updates, property disputes, and benefits eligibility.
The process looks like a divorce filing in form, though the legal theory is different. You file a petition in the family court where you or the other party lives, usually with certified copies of both marriage certificates and evidence that no divorce was ever entered for the first marriage. The other party gets notice and a chance to respond. Either spouse from the void marriage can file, and in some jurisdictions the legal spouse from the first marriage can seek the declaration as well.
Filing fees generally run a few hundred dollars. Attorney fees depend on complexity: an uncontested case with clear facts may be handled for a flat fee, while disputes over property, custody, or putative spouse claims push costs higher. The court can resolve custody, support, and property division as part of the proceeding, which is often reason enough to pursue it even when the void status seems obvious on its face.