Same-sex couples in Washington state have begun tying the knot on the first day they could legally wed after the state's voter-approved gay marriage law came into effect.
Hundreds of gay and lesbian couples picked up their marriage licences as early as 12:01am on Thursday.
But the state's three-day waiting period meant the earliest weddings could take place was just after midnight on Sunday.
Some courts, including those around Seattle and the state's capital of Olympia, started marrying couples at midnight.
In November Washington, Maine and Maryland became the first US states to grant marriage rights to same-sex couples by a popular vote.
"We're so proud to live in this state that recognises love and commitment," said Sarah Cofer after she and Emily Cofer uttered the words "I will" on Sunday.
The Cofers' union was the state's first same-sex wedding.
Officiating at their nuptials at Seattle's King County Courthouse was the aptly-named Judge Mary Yu.
They were followed by 11 other couples scheduled to wed at 30-minute intervals through the night in Ms Yu's 9th-floor courtroom.
Ms Yu said: "I'm proud to be a witness to an extraordinary event in our history."
In Olympia, five couples were married early on Sunday, including Jonathon Bashford and Matthew Wiltse.
The couple, together for 10 years, held a commitment ceremony in September when they registered as domestic partners, but said they wanted to be among the first to legally marry.
"We weren't going to wait one second longer," Mr Wiltse said.
Gay marriage is legal, or will be soon, in nine states - Connecticut, Iowa, Maine, Maryland, Massachusetts, New Hampshire, New York, Vermont, Washington - and the District of Columbia.
But 31 states have amended their constitutions to prohibit same-sex marriage.
The issue of same-sex unions promises to remain at the nation's political forefront.
On Friday, the US Supreme Court said it would take up California's in-limbo same-sex marriage ban, which was struck down by a federal appeals court.
The Supreme Court will also decide in its upcoming session whether Congress can deprive married gay couples of certain federal benefits available to straight couples.
A provision of the federal Defence of Marriage Act limits a range of health and pension benefits, as well as favourable tax treatment, to heterosexual couples.