How is same-sex marriage in the US changing?

Married same-sex households have outnumbered unmarried same-sex households since 2016.

Updated March 7, 2025 by the USAFacts team

In 2015, the Supreme Court ruled on Obergefell v. Hodges, thereby legalizing same-sex marriage nationwide. In the years since the decision, households headed by married same-sex couples have become more common, but the changes have differed by state.

How have the number of same-sex households changed since 2015?

By the end of 2015, the year of the Obergefell v. Hodges ruling, the nation’s number married same-sex households increased by 27.0%, the third largest increase on record. The largest were in 2013 and 2014 following 29 states legalizing these unions.

Households headed by same-sex couples have increased 131.3%, from 334,829 in 2014 before the ruling to 774,553 in 2023. The number of households nationwide headed by same-sex married couples surpassed same-sex unmarried couples for the first time in 2016 and it’s remained that way through 2023 (the latest year such data is available).

However, the number of households with same-sex couples was rising years before Obergefell v. Hodges. It was even rising years before 2013. States started legalizing same-sex marriage in the mid-2000s. In 2008, the Census changed the methodology for counting same-sex households and marriage rates rose accordingly. The number of same-sex married couples has increased each year except between 2018 and 2019.

When did each state allow same-sex marriage?

In 2004, Massachusetts was the first state to legalize same-sex marriage. Several other Northeast states shortly followed suit: Connecticut in 2008, Vermont in 2009, and New Hampshire and Washington, DC, in 2010. Iowa also legalized same-sex marriage in 2009.

Same-sex marriage was legal in California from June 16, 2008, to November 4, 2008, but was overturned by Proposition 8. The state legalized again in June 2013. Six other states — Arkansas, Colorado, Indiana, Michigan, Utah, and Wisconsin — had court actions that temporarily allowed same-sex marriages.

By the time same-sex marriage was legalized federally, it had already been legal in 38 states and Washington, DC.

As of 2022, 34 states had laws or constitutional amendments prohibiting same-sex marriage. These are superseded by federal law and may also be affected by prior state supreme court or lower federal court rulings.

Which states have the highest share of married same-sex couples?

As of 2023, the highest shares of married households headed by same-sex couples were in Washington, DC, (5.96% of married couples are same sex) and Delaware (2.34%).

Other Northeast states had comparatively higher percentages:

Vermont (2.11%)
Maine (1.88%)
Massachusetts (1.83%)
Rhode Island (1.81%)
New York (1.69%)

On the west side of the country the states with the highest percentage of same sex couples were:

Nevada (1.95%)
Washington (1.77%)
California (1.66%)
Oregon (1.64%)

Colorado is an outlier compared to the states surrounding it, with 1.53% of marriages being same-sex couples.

North Dakota had the lowest percentage of same-sex couple households (0.26%), followed by South Dakota (0.59%), and Iowa (0.64%).

How has same-sex marriage changed over time by state?

The number of Iowa households headed by someone in a same-sex marriage fell from 4,653 households in 2014 to 4,123 in 2023 — down 11%.

However, Iowa was the exception to the rule, as these households grew in every other state.

Montana had the largest increase, 466.5%, or more than five times the share it had in 2014. Montana started with one of the lowest counts, however — 540 married households in 2014 — which grew to 3,059 by 2023. Nevada followed at 361.5%, and Georgia was third at 258.9%.

The number of same-sex marriage households doubled in all but 10 states.

The states with the smallest percentage increases were North Dakota (16.0%), Connecticut (16.6%), and New Hampshire (49.6%).

States with the largest populations tend to have the most households with same-sex marriages. For example, in 2023, California’s population was about 39 million, highest in the nation. It had 109,120 married same- sex households, also most in the nation. This was 76% higher than second-ranked Texas, which was also 2023’s second most populous state.

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