A civil partnership is a legally recognized relationship between two people, registered with a state or local government, that grants many of the same state-level rights as marriage — things like inheritance when a partner dies without a will, hospital visitation, and shared parental responsibilities — without being a marriage. The catch is federal law. The federal government does not treat civil partners as spouses, so joint tax filing, Social Security survivor benefits, immigration sponsorship, and the unlimited estate tax marital deduction are either unavailable or uncertain. Whether a civil partnership is the right choice depends almost entirely on which of those federal benefits you need.
What the Term Actually Covers
There is no single federal civil partnership system. Each state that offers this status has built its own version under its own name, and the labels matter less than the statute behind them.
A civil union typically mirrors nearly all state-level marriage rights and is available in states including Colorado, Hawaii, Illinois, New Jersey, and Vermont. A domestic partnership may offer a narrower or broader set of rights depending on where you register and is available in California, the District of Columbia, Maine, Nevada, Oregon, Washington, and Wisconsin. Hawaii also recognizes a separate category called reciprocal beneficiary relationships.
Different names, same basic idea: a state-recognized legal relationship without a marriage certificate. What you actually get depends on your state’s statute, so check your local rules before relying on any specific protection.
State-Level Rights You Receive
When a state grants civil partnership status, it generally attaches a bundle of rights that parallel what married couples receive under that state’s laws. The most common protections include:
- Inheritance. If your partner dies without a will, state intestacy laws generally treat you the way they would treat a surviving spouse. In states where civil unions carry full spousal equivalence, you receive the same share a married spouse would.
- Parental rights. A partner who is not the biological parent may gain legal standing over children born into the union, including shared decision-making for education and healthcare. The specifics depend on state parentage and adoption laws.
- Property and debt. Partners typically share responsibility for debts incurred during the union and may be subject to the same property division rules as married couples if the relationship ends.
- Medical visitation. Most states grant civil partners the right to visit each other in the hospital and to be treated as family for visitation purposes.
Every one of those protections is a creature of state law. Cross a state line, and the picture can change entirely.
Where Federal Law Draws the Line
The most important thing to understand before registering is that the federal government does not treat a civil partnership as a marriage. In 2013, the IRS issued Revenue Ruling 2013-17, which explicitly stated that the terms “spouse” and “marriage” do not include individuals who have entered into a registered domestic partnership, civil union, or other similar formal relationship that is not called a marriage under state law.1Internal Revenue Service. Revenue Ruling 2013-17 That one line sets up every federal gap that follows.
Taxes
Civil partners cannot file federal tax returns as married filing jointly or married filing separately. Each partner files as single or, if eligible, as head of household.2Internal Revenue Service. Answers to Frequently Asked Questions for Registered Domestic Partners and Individuals in Civil Unions When one partner earns significantly more than the other, this often produces a higher combined tax bill than a married couple would owe on the same income.
There is a second tax cost many couples don’t see coming. When an employer provides health insurance to an employee’s married spouse, the employer’s contribution is excluded from the employee’s taxable income. For a civil partner who does not qualify as a tax dependent, the employer’s share of the premium is treated as imputed income: it shows up on your W-2, and you pay income and employment taxes on it.
Estate Transfers
Married spouses can leave an unlimited amount of property to each other free of federal estate tax through the unlimited marital deduction. Civil partners do not qualify.3Internal Revenue Service. Frequently Asked Questions on Estate Taxes Transfers to a civil partner instead run against the standard estate tax exemption. For most estates that difference is invisible, but for wealthier couples it can produce a federal tax bill that a married couple would avoid entirely.
Social Security Survivor Benefits
The Social Security Administration allows surviving spouses to claim survivor benefits if they were married for at least nine months before the worker’s death and meet age requirements.4Social Security Administration. Who Can Get Survivor Benefits The SSA has said some same-sex couples in non-marital legal relationships such as civil unions “may qualify” for benefits and encourages them to apply.5Social Security Administration. Do I Qualify for Benefits as a Spouse if I Am in a Civil Union or Domestic Partnership Eligibility is evaluated case by case. It is not guaranteed. If survivor benefits are central to your retirement plan, marriage provides far more certainty.
Immigration
U.S. immigration law allows a citizen to petition for a green card for a spouse, but only a legally married spouse qualifies as an “immediate relative.”6U.S. Citizenship and Immigration Services. Green Card for Immediate Relatives of U.S. Citizen A civil partner cannot sponsor their partner for an immigrant visa, no matter how long the relationship has lasted.
Healthcare Decisions Are Not Automatic
A common assumption is that registering a civil partnership automatically gives your partner the right to make medical decisions for you if you become incapacitated. It is not reliably true. Under federal HIPAA rules, a “personal representative” authorized to access your medical information and make healthcare decisions must have legal authority granted under state law, such as a healthcare power of attorney or court-appointed guardianship.7U.S. Department of Health and Human Services. Personal Representatives
Some states automatically designate a civil partner as the default healthcare decision-maker, similar to a spouse. Others do not, leaving your partner with no more authority than a friend. To be safe in any state, pair your civil partnership with a durable power of attorney for healthcare and a HIPAA authorization form naming your partner by name. These documents are inexpensive and remove any ambiguity in an emergency.
Who Can Register, and How
Eligibility details vary by state, but the pattern is consistent. Both partners must be at least 18, though a small number of states allow registration at 17 with parental or judicial consent. Both must have the mental capacity to understand what they are entering. Close blood relatives — siblings, parents and children, and other direct relatives — cannot register together. And both partners must be legally free: not already married and not in an existing civil union or domestic partnership. If a prior relationship ended by divorce, dissolution, or death, you will need documentation showing it is no longer active.
Registration itself usually takes place at a county clerk’s office or local registrar in a state that offers civil unions or domestic partnerships. The general steps:
- Bring identification. Both partners need a valid government-issued photo ID. Some states also require proof of residency.
- Prove eligibility. If either partner was previously married or in a civil union, bring a certified copy of the divorce decree, dissolution order, or death certificate.
- Complete the application. The form typically asks for legal names, dates of birth, addresses, and sometimes occupations.
- Pay the fee. Fees vary by jurisdiction, generally in the range of $30 to $125.
- Sign, and sometimes appear. Some states require both partners to sign in front of a registrar. A few require witnesses.
Once the paperwork is processed, the registrar issues an official certificate. Processing times run from same-day to several weeks, and some states impose a short waiting period before the partnership takes effect.
Moving Between States
One of the practical weaknesses of a civil partnership is portability. Unlike marriage, which every state must recognize under the U.S. Constitution, there is no federal requirement that a civil union or domestic partnership registered in one state be honored in another. A state that does not offer civil partnerships has no obligation to recognize yours, and many do not.
The consequences are concrete. If you register a domestic partnership in California and then move to a state that does not recognize that status, you could lose access to hospital visitation rights, inheritance under intestacy, and property division rules. Courts sometimes recognize an out-of-state partnership for limited purposes, like granting a dissolution, but ongoing benefits are less likely to transfer. If you and your partner live in or might move between different states, check both states’ recognition rules before choosing a civil partnership over marriage. Carrying copies of your advance directives and powers of attorney becomes especially important when you travel.
Converting to Marriage
Several states that once offered civil unions have since converted existing civil unions into marriages automatically. In states that still offer both options, converting usually means visiting the county clerk or registrar, presenting your civil partnership certificate and ID, and completing a marriage license application. A new marriage certificate is issued, and the partnership is superseded.
Conversion is worth considering if the federal benefits above — joint tax filing, the unlimited marital deduction, Social Security survivor benefits, immigration sponsorship — matter to your situation. The process is generally simpler and cheaper than a brand-new marriage application because you have already established eligibility and a legal relationship.
Ending a Civil Partnership
A civil partnership does not end by walking away. It requires a formal court process similar to divorce. You file a petition for dissolution with the court in the state where the partnership is registered or where you currently reside, depending on state rules. Most states use the same grounds as divorce — typically irretrievable breakdown of the relationship — and the same procedures for dividing property, determining support obligations, and allocating parental responsibilities.
Jurisdiction is where civil partnerships get awkward. If you registered in one state but now live somewhere that does not recognize your partnership, you may need to return to the original state to dissolve it, or ask a court in your current state to take jurisdiction, which is not always possible. Thinking about where you might live before you register can save considerable legal expense later.