Domestic Partner in Illinois: Civil Unions, Rights, and Parentage

Illinois does not offer a statewide domestic partnership. If you want legal recognition as a domestic partner in Illinois, the state-level option is a civil union under the Illinois Religious Freedom Protection and Civil Union Act, which gives partners the same obligations, protections, and benefits that Illinois law gives to married spouses.¹ Civil unions are available to same-sex and different-sex couples alike. A handful of cities keep their own domestic partner registries for narrow local purposes, but a civil union is the only relationship that carries weight across the whole state.

Civil Union or Local Domestic Partnership

The two terms describe different things, and mixing them up leads people to register for something that does not do what they expected.

A civil union is a state-level legal relationship with broad rights under Illinois law, including inheritance, healthcare decision-making, and property protections.¹ A domestic partnership in Illinois usually means a city registry with limited reach. Chicago’s Domestic Partners Ordinance, for example, primarily extends health coverage and related benefits to qualified partners of city employees and requires partners to file an affidavit, prove shared residence, and show joint financial ties.² Useful if you qualify, but it does not give you inheritance rights, parentage presumption, or tax status.

If statewide legal protection is what you are after, the civil union is the path.

Who Can Enter a Civil Union

Both partners must be at least 18. The civil union statute, unlike Illinois marriage law, contains no exception for 16- or 17-year-olds with parental consent.¹ Neither partner can already be in a marriage, civil union, or similar relationship that has not been dissolved.

Close relatives are barred. You cannot enter a civil union with:

An ancestor or descendant (parent, grandparent, child, grandchild)
A sibling, whether full, half, or by adoption
An aunt, uncle, niece, or nephew, by blood or adoption
A first cousin

That last one is a real difference from marriage law. Illinois allows first-cousin marriages under certain conditions; first-cousin civil unions are flatly banned.¹

How to Apply

Both partners must appear together, in person, at the County Clerk’s office in the county where the ceremony will take place. No mail-in, no sending one partner alone. Each of you should bring:

A government-issued photo ID (driver’s license, state ID, or current passport)
Proof of age (birth certificate, passport, or military ID)
A certified copy of any divorce decree, annulment order, or death certificate ending a prior marriage or civil union

Some counties only ask for a dissolution document when the prior relationship ended within the last six months; others want it regardless.³ Bring it either way. You will also give the clerk your Social Security numbers and full legal names.

Fees vary. Coles County charges $60, LaSalle County charges $35.⁴⁵ Call ahead to confirm the amount and accepted payment methods. Some offices take only cash or check.

License Timing and Ceremony

Once issued, the license takes effect one day later and expires 60 days after that.¹ The ceremony must happen inside that window and inside the county that issued the license.⁶

Judges, clergy or officiants in good standing with a religious denomination, and public officials whose duties include solemnizing marriages can perform the ceremony. In counties with a population of two million or more, which currently means Cook County, the county clerk can officiate as well.

After the ceremony, the officiant has 10 days to complete the certificate and return it to the county clerk.¹ Miss that deadline and official registration can be delayed, so confirm with whoever marries you that they know the rule.

What Rights You Get Under Illinois Law

The statute gives civil union partners the same obligations, protections, and benefits Illinois gives married spouses, whether those rights come from statute, administrative rules, or common law.¹ In practice, that covers:

Healthcare decisions for your partner in emergencies, hospital visitation, and access to medical records as the patient’s personal representative under state law, which federal HIPAA rules then recognize.⁷
Intestacy rights if your partner dies without a will, including preference to be appointed administrator of the estate.
Illinois state income tax filing as a married couple.
The ability to hold real estate as tenants by the entirety, a form of ownership that shields the home from creditors with a judgment against only one partner.

These rights are broad, but they stop at the Illinois border and at the federal line.

Where Federal Law Leaves You Out

This is the biggest limitation of a civil union compared with marriage.

The IRS does not treat civil unions as marriages. Civil union partners cannot file a joint federal return and must file as single, head of household, or qualifying surviving spouse based on their own circumstances. You can end up filing jointly for Illinois and separately for federal in the same tax year.

The federal Family and Medical Leave Act also does not cover civil union partners. If your partner has a serious medical condition, your employer is not required by FMLA to grant you unpaid leave to care for them, because the law’s definition of “spouse” does not reach civil unions.

Social Security sits in a grayer area. The Social Security Administration has said some people in non-marital legal relationships may qualify for spousal or survivor benefits if they meet certain requirements, and the agency encourages civil union partners to apply even when eligibility is unclear.⁸ If you were previously denied survivor benefits, SSA says to contact them to revisit the claim.

For couples who need federal benefits to line up with the state-level ones, converting the civil union to a marriage closes the gap.

Children and Parentage

Illinois presumes parentage for civil union partners. A child born while partners are in a civil union, or within 300 days after it ends, is legally presumed to be the child of the birth parent’s partner.⁹ The presumption works the same way it does for married couples.¹⁰

Even so, many family law attorneys recommend that non-biological parents in civil unions complete a second-parent adoption. The parentage presumption is reliable inside Illinois but may not be honored in states that do not recognize civil unions. An adoption decree is a court order other states must respect under the Full Faith and Credit Clause. If your family travels often or might move, the extra protection is worth considering.

Converting a Civil Union to a Marriage

Partners already in a civil union can convert it to a marriage by applying for a marriage license and holding a marriage ceremony like any other couple. The license application fee is waived for the conversion, and the people marrying must be the same two people who entered the original civil union.¹¹ Once the marriage is registered, the civil union ends and you are legally married as of the date on the marriage certificate.

You cannot marry someone else while your civil union is still active. To marry a new partner, you have to dissolve the civil union through the courts first.

Out-of-State Recognition

Illinois recognizes civil unions and substantially similar legal relationships validly entered in other states or jurisdictions.¹² A domestic partnership or civil union from Colorado, New Jersey, or another state offering such status is treated as a civil union here. Common-law marriages are the one carveout and are not covered.

The reverse is not guaranteed. If you enter a civil union in Illinois and move to a state that does not recognize them, you can lose those state-level protections. Dissolution gets harder too, since some courts will not end a legal relationship they do not acknowledge. For couples with any realistic chance of relocating, that is a strong reason to convert to marriage.

Ending a Civil Union

Ending a civil union is a court case in the Illinois Circuit Court. The statute uses the same rules that govern divorce, including the grounds for dissolution, property division, maintenance, and related procedures from the Illinois Marriage and Dissolution of Marriage Act.¹³ The Illinois Courts website publishes standardized forms, including one specifically for dissolution of a civil union.¹⁴

At least one partner must have lived in Illinois for 90 days before the court can enter a final judgment. You can file the petition before the 90 days are up, but the court will not finalize anything until the residency requirement is satisfied. If you have children, parental responsibilities and child support are decided under the same guidelines used for any other family case.

The court divides assets and debts accumulated during the union equitably, and maintenance decisions turn on factors like the length of the relationship and each partner’s finances. Because the process tracks divorce closely, most people are better off working with an attorney, especially when children or significant property are involved.

1
Illinois General Assembly. 750 ILCS 75 – Illinois Religious Freedom Protection and Civil Union Act
2
City of Chicago. Domestic Partners Ordinance
3
Peoria County, IL. Peoria County Civil Union Licenses
4
Coles County Clerk. Marriage Licenses and Civil Unions
5
LaSalle County, IL. Civil Union License Information
6
Kane County Clerk. Apply for a Civil Union License
7
U.S. Department of Health and Human Services. Guidance on HIPAA, Same-Sex Marriage, and Sharing Information with Patients’ Loved Ones
8
Social Security Administration. Do I Qualify for Benefits as a Spouse if I Am Now in, or the Surviving Spouse of, a Civil Union, Domestic Partnership, or Other Non-Marital Legal Relationship?
9
Illinois General Assembly. 750 ILCS 46/204 – Presumption of Parentage
10
Illinois Department of Healthcare and Family Services. Parentage Information You Should Know
11
Illinois General Assembly. 750 ILCS 75/65 – Voluntary Conversion of Civil Union to Marriage
12
Illinois General Assembly. 750 ILCS 75/60 – Laws of Other Jurisdictions
13
Illinois General Assembly. 750 ILCS 75/45 – Dissolution and Declaration of Invalidity
14
State of Illinois Office of the Illinois Courts. Divorce, Child Support, and Maintenance