The US census shows that there are 131,297 gay married households and 514,735 unmarried gay households.

Marriage equality campaigners said the figures show the need for gay couples to be given the right to wed.

Evan Wolfson, president of Freedom to Marry, said: “The Census Bureau’s most recent estimates of same-sex couples reiterate the need to end marriage discrimination once and for all. The number of gay and lesbian couples in committed, loving relationships, raising families together, continues to grow, leaving more and more families without the critical safety-net of marriage.”

He added: “These findings also confirm that those who most need the support marriage offers – particularly in these tough economic times – live in the places with the fewest protections.

“The South is home to more gay parents than any other region in the nation. And yet, these families are not only discriminated against by their home states, which exclude them from marriage and bar even lesser protections such as civil union and domestic partnership, but are also targeted for an additional layer of discrimination from the federal government under the so-called Defense of Marriage Act.”

Initial Census Bureau reports vastly overestimated the number of married gay couples, putting it at 349,377. Officials put the error down to an inconsistency in the statistics.

This is the first time census data on gay households has been collected.

Rea Carey, executive director of the National Gay & Lesbian Task Force, said the data would give gay couples far more visibility.

“No longer are our marriages rendered invisible in the snapshot of our country provided through the Census,” she said. “And no longer can anyone ignore the presence of our relationships all across the country.”