Seattle's King County opened its auditors office just after midnight to start distributing marriage licenses to hundreds of people who had lined up hours earlier, reports AP.
"We knew it was going to happen, but it's still surreal," Amanda Dollente told the Associated Press. Dollente and her partner Kelly Middleton began standing in line at 4 p.m. Dec. 5.
By 6 a.m., 279 licenses had been issued but wedding bells won't be ringing until later this weekend.
Washington law says that couples must submit their marriage licenses three days in advance, so the first same-sex marriage celebrations are scheduled for Sunday.
In the state capitol of Olympia, Thurston County opened its office at midnight to grant licenses to 15 couples who entered a lottery to be the first-served.
"This is an historic occasion," Thurston County Auditor Kim Wyman, a Republican, told Reuters. "Some of these couples have been together for more than 20 or 30 years. It's pretty moving when you hear those stories."
West Seattle residents Pete-e Petersen and Jane Abbott Lighty, who are acknowledged as the matriarchs of the movement, were among the first to marry in Seattle, reports the Seattle Times.
"It's very humbling to be chosen first. We feel like we're representing a lot of people in the state who have wanted this for a long time," said Petersen, 85, who has been with Lighty for 35 years. "It's hard to explain the thrill that we are really going to get married."
Nationally syndicated sex columnist Dan Savage and his partner Terry Miller were also out in Seattle to pick up a marriage license.
"It's really a remarkable journey we've been on and such a remarkable sea change," Savage told Seattle PI. "And not just for gay people, but straight people have changed, too. It's gotten better for us because straight people have gotten better about us."
Offices across the state were staying open all night to accommodate all of the couples who wanted to get married as soon as possible.
County staffers told the Seattle Times that they were happy to work the extra hours.
"This is marriage," county spokesman Cameron Satterfield told the newspaper. "It's one of the few happy things that we get to do in government."
Voters in Washington, Maryland and Maine made history last month by approving gay marriage by popular vote.
Washington is the first state to put the new law into effect. Maine will start issuing same-sex marriage licenses on Saturday, Dec. 29 and in Maryland on Tuesday, Jan. 1, 2013, reports Reuters.