U.S. marriage laws are set almost entirely by the states, which decide who can marry, what a license costs, who can officiate, and how a marriage ends, while federal law layers on constitutional protections, tax rules, Social Security benefits, and immigration pathways. Every state requires a license, a ceremony performed by an authorized person, and registration of the completed paperwork with a government office. The specifics vary enough that a five-minute call to your county clerk before you start is worth making.
Who Can Legally Marry
Three eligibility rules run through every state: age, mental capacity, and the absence of a prohibited family relationship or an existing marriage.
Age
Eighteen is the default minimum age everywhere. As of 2025, thirteen states and the District of Columbia treat that as an absolute floor with no exceptions. The remaining states still allow minors to marry in limited circumstances, usually with parental consent, judicial approval, or both. Where a court is involved, a judge typically evaluates whether the minor understands the commitment and is not being pressured into it. The trend over the past decade has been toward eliminating exceptions, and more states move in that direction each session.
Mental Capacity
Both people must be able to understand what the marriage contract involves, including its financial obligations and mutual duties. Severe intoxication at the ceremony, significant cognitive disability, or any condition that prevents a person from grasping the nature of the commitment can make the marriage legally invalid. No state uses a standardized test; disputes surface after the fact, when someone challenges whether a spouse truly understood what they agreed to.
Prohibited Relationships
Every state prohibits marriage between close blood relatives: parent and child, siblings (whole or half-blood), and grandparent and grandchild. Aunts, uncles, nieces, and nephews are barred in most places. First-cousin marriage is where the laws split. Roughly half the states ban it, about a third allow it, and several others permit it only under conditions like age thresholds or proof the couple cannot have children.
Void and Voidable Marriages
A marriage that violates a core eligibility rule, like bigamy or a prohibited family relationship, is typically void. The law treats it as though it never happened, so neither spouse needs to file for divorce or annulment. In some states, entering an incestuous or bigamous marriage can also lead to criminal charges.
A voidable marriage is different. It was technically valid when performed, but one spouse can ask a court to annul it on specific grounds, such as fraud, duress, an underage party who lacked proper consent, or a physical inability to consummate the marriage. Until someone challenges a voidable marriage in court, it remains legally recognized. Time limits for filing an annulment vary by state and by the specific ground, so acting quickly matters.
Same-Sex and Interracial Marriage Are Federally Protected
Since 2015, the constitutional right to marry has applied equally regardless of sex. In Obergefell v. Hodges, the Supreme Court held that the Fourteenth Amendment requires every state both to issue marriage licenses to same-sex couples and to recognize same-sex marriages performed in other states.1Justia US Supreme Court Center. Obergefell v. Hodges, 576 U.S. 644 (2015)
Congress reinforced that protection in 2022 by passing the Respect for Marriage Act, which repealed the Defense of Marriage Act. Under 28 U.S.C. ยง 1738C, no state may deny full faith and credit to a marriage from another state based on the sex, race, ethnicity, or national origin of the spouses, and both the Attorney General and individual spouses can sue in federal court for violations.2Office of the Law Revision Counsel. 28 USC 1738C – Certain Acts, Records, and Proceedings and the Effect Thereof A same-sex or interracial couple married in any state has guaranteed federal recognition of that marriage everywhere in the country.
Getting a Marriage License
What to Bring
The process starts at your local county clerk’s office, and both partners almost always need to appear in person. At minimum, each applicant needs a government-issued photo ID like a driver’s license, state ID card, or passport. Some offices accept military IDs or immigration documents. A birth certificate is not universally required if you have valid photo identification, but a few jurisdictions ask for one, especially for applicants who lack other proof of age.
If either person was previously married, you’ll need documentation showing the prior marriage ended, usually a certified copy of a divorce decree or, if the former spouse died, a death certificate. The clerk will not issue a new license until satisfied no earlier marriage is still in effect. You’ll also be asked for your Social Security number along with basic biographical details like your parents’ full names and birthplaces.
Fees, Waiting Periods, and Expiration
License fees generally fall between $30 and $100, with most counties around $50 to $60. Some locations offer a discount for couples who complete a premarital education course.
About a third of states impose a waiting period between license issuance and the ceremony, ranging from one to three days. The rest let you marry immediately. A few states waive the waiting period under specific circumstances, such as a court order or completion of premarital counseling.
Every license also has an expiration date. If you don’t hold the ceremony in time, the license becomes void and you’ll need to reapply and pay again. Some states give you 30 days, most fall around 60, and a handful allow six months or even a year. Confirm with the issuing office so you aren’t caught off guard.
The Ceremony and the Certificate
A license authorizes a marriage; the ceremony creates it. The law requires an officiant authorized by the state. That typically includes ordained or licensed clergy, judges, magistrates, justices of the peace, and in some states, court clerks. A few states let couples designate someone to receive a temporary authorization for a single ceremony. Online ordinations are accepted in many jurisdictions, though a handful have challenged their validity in court.
Most states also require one or two adult witnesses present to sign the license after the ceremony. The officiant and witnesses sign, and the officiant returns the completed document to the clerk’s office. That filing step turns the license into a marriage certificate, which is the official government record you’ll use for insurance enrollment, name changes, property transactions, and benefit claims. If the officiant fails to file, the marriage is still legally valid in most states, but obtaining an official certificate becomes more complicated.
Recognition Across State Lines
Article IV, Section 1 of the U.S. Constitution requires every state to give full faith and credit to the public acts, records, and judicial proceedings of every other state.3Congress.gov. U.S. Constitution – Article IV In practice, a couple legally married in one state does not need to remarry when they move. The new state must recognize the marriage for all purposes, including tax filing, healthcare decisions, inheritance, and property ownership. The Respect for Marriage Act closes any remaining loophole by prohibiting refusal based on the sex, race, ethnicity, or national origin of the spouses.2Office of the Law Revision Counsel. 28 USC 1738C – Certain Acts, Records, and Proceedings and the Effect Thereof
Common Law Marriage
A small number of states still recognize common law marriage, which allows a couple to be considered legally married without a license or ceremony. Roughly eight to ten states and the District of Columbia recognize some form of it, either by statute or through court decisions.4National Conference of State Legislatures. Common Law Marriage by State Colorado, Iowa, Kansas, Montana, South Carolina, Texas, and Utah all have statutory provisions, while a few others recognize it through case law.
Simply living together for a long time does not create a common law marriage anywhere. The couple must genuinely intend to be married and present themselves to the world as a married couple, through actions like sharing a last name, referring to each other as spouses, and filing joint tax returns. Without that deliberate intent, decades of cohabitation won’t produce marital rights. In the vast majority of states, common law marriage isn’t available at all, so the only path runs through the clerk’s office.
Changing Your Name
Marriage does not automatically change anyone’s legal name. If you want to take your spouse’s surname or adopt a hyphenated name, you’ll need to update your records with multiple agencies. Start with the Social Security Administration, because most other institutions require your Social Security name to match before processing a change.
The SSA recommends waiting at least 30 days after your wedding to apply so states have time to update their vital records.5Social Security Administration. Just Married? Need to Change Your Name? You’ll need your marriage certificate and proof of identification. Some states allow the process online; others require an in-person visit. After your Social Security record is updated, move on to your driver’s license, passport, bank accounts, and employer records. Voter registration also needs updating, which may mean re-registering entirely or submitting a change form online, by mail, or in person.6USAGov. How to Update or Change Your Voter Registration
Prenuptial and Postnuptial Agreements
A prenuptial agreement is a contract signed before the wedding that spells out how assets, debts, and financial obligations will be handled if the marriage ends. A postnuptial agreement covers the same ground but is signed after the wedding. At least 26 states and the District of Columbia have adopted some version of the Uniform Premarital Agreement Act, which creates a baseline set of enforceability rules, though each state may add its own requirements.
For either type of agreement to hold up, both spouses generally need to have entered into it voluntarily with full knowledge of the other person’s financial situation. Hiding assets or debts is the fastest way to get one thrown out. Courts also look at whether each person had an opportunity to consult a lawyer independently and whether the terms are reasonably fair. An agreement signed under pressure the night before a wedding faces much steeper scrutiny than one negotiated months in advance with both sides represented.
There are limits. No prenup or postnup can determine child custody or child support, because courts decide those issues based on the child’s best interests at the time of divorce. Some states restrict waiving alimony entirely. And the agreements must be in writing; oral promises about property division carry no legal weight.
Taxes, Debt, and Benefits
Federal Income Tax
Marriage changes your filing options. For 2026, the standard deduction for married couples filing jointly is $32,200, compared to $16,100 for a single filer.7Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill Because $32,200 is exactly double $16,100, two people earning similar moderate incomes won’t see a penalty from filing jointly. A marriage bonus usually shows up when one spouse earns significantly more than the other, because the higher earner’s income gets spread across wider brackets.
A marriage penalty hits couples where both spouses earn high incomes. The 37% top bracket kicks in at $640,600 for a single filer but at $768,700 for a married couple filing jointly, well short of double the single threshold.7Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill Whether marriage helps or hurts your tax bill depends on how your incomes compare.
Debt and Community Property
Responsibility for a spouse’s debts depends on your state’s property system. Nine states follow community property rules: Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin. In those states, debts either spouse takes on during the marriage are generally treated as shared obligations, and creditors can pursue marital assets to collect. Pre-marriage debts, inheritances, and gifts received by one spouse usually remain separate.
In the remaining states, which follow common law property rules, you’re generally not responsible for debts your spouse incurred alone unless you co-signed the loan or the debt covered family necessities like housing or medical care. Joint accounts and jointly titled property are fair game for either spouse’s creditors.
Social Security Spousal Benefits
Marriage opens the door to Social Security spousal benefits, worth up to half of the higher-earning spouse’s primary insurance amount. To qualify, you generally must have been married for at least one year, unless you’re the parent of your spouse’s child.8Social Security Administration. What Are the Marriage Requirements to Receive Social Security Spouse’s Benefits The claiming spouse must be at least 62 or caring for a qualifying child under 16. If your own retirement benefit based on your own earnings record is higher than the spousal benefit, you’ll receive yours instead.9Social Security Administration. Benefits for Spouses
Divorced spouses can also claim benefits on an ex’s record, but only if the marriage lasted at least ten years.8Social Security Administration. What Are the Marriage Requirements to Receive Social Security Spouse’s Benefits Ending a nine-year marriage means permanently forfeiting a benefit that could be worth hundreds of dollars a month in retirement.
Health Insurance
Getting married triggers a Special Enrollment Period, giving you 60 days from the wedding to enroll in a spouse’s employer plan or select a new marketplace plan. Coverage under the new plan typically begins the first day of the month after enrollment. Miss the window and you’ll generally wait until the next open enrollment period. One detail worth knowing: you can stay on a parent’s health plan until age 26 regardless of whether you get married, so couples where one spouse is under 26 can keep that arrangement while enrolling the other spouse separately.
Marrying a Non-Citizen
Marriage to a U.S. citizen makes a foreign national an “immediate relative” under immigration law, which is the fastest pathway to a green card because there’s no annual visa cap or waiting list for this category.10U.S. Citizenship and Immigration Services. Green Card for Immediate Relatives of U.S. Citizen The citizen spouse files Form I-130 to establish the relationship, and the foreign national files Form I-485 to adjust status to permanent resident if already in the country. Spouses living abroad go through consular processing instead.
The marriage must be genuine. USCIS interviews both spouses, often separately, and looks for evidence that the relationship is real rather than arranged solely for immigration purposes. Fraudulent marriages carry serious criminal penalties and can result in deportation and a permanent bar from future immigration benefits. The foreign national spouse must also be admissible to the United States, meaning no disqualifying criminal history or prior immigration violations, though waivers exist for some grounds of inadmissibility.