More than 600 gay couples rushed to town halls and courthouses across Massachusetts on Monday and emerged to cheering crowds, live bands and rice-throwing relatives as the state became the first in the nation to allow same-sex marriages.

Along with the party atmosphere came moments of somber reflection and deep emotion as the day marked two sorts of milestones: the leaping of a long-unthinkable barrier in American culture and the passage of a long-awaited turning point in many lives.

It was a day in which stereotypes were not only broken but also turned inside out, in which liberal lesbians expressed unstinting patriotism and conservative clergy members denounced the nation's moral and political trajectory. The United States is now one of a handful of countries -- along with Belgium, the Netherlands and Canada -- to give some gay marriages the full protection of law.

The first to wed were Tanya McCloskey, 52, and Marcia Kadish, 56, of Malden, who said they had not sought the limelight but merely wanted to get the ceremony over with so they could enjoy the rest of the day. "I now pronounce that you are married under the laws of Massachusetts," Cambridge City Clerk Margaret Drury declared at 9:10 a.m. "You may seal this marriage with a kiss."

The newlyweds embraced, and Kadish jumped up and down excitedly. "Thank you. Thank you," she said. Said McCloskey: "What a way to celebrate the freedoms we have in this country. This country is fabulous. I'm just so proud to be a citizen of the United States of America."

But while those on both sides of an issue that has divided the nation acknowledged the historic nature of the ceremonies, many questions about the future of same-sex marriage remain. A federal appeals court will consider a request to stop the marriages in June, and a state constitutional amendment banning gay marriage could go to a referendum in November 2006.

President Bush seized the occasion to renew his call for an amendment to the U.S. Constitution defining marriage as the union of one man and one woman. And a small but vocal number of protesters in Massachusetts gave notice that their fight against the state court decision that legalized same-sex marriage here was just beginning.

Across the state, gay couples lined up -- some as early as Saturday -- outside municipal clerks' offices to register to marry. By evening, 227 couples had filed papers in Cambridge, 154 in Provincetown, 113 in Northampton, 99 in Boston, 65 in Worcester, 37 in Somerville, and scores more elsewhere.

Some also dashed to court to obtain waivers of the three-day waiting period for a marriage license. They then went to justices of the peace to get married. Provincetown and Worcester reported the most same-sex weddings -- about 30 each -- and Cambridge had 22.

Across the state, cheering crowds serenaded and saluted gay couples leaving courthouses. Police estimated that nearly 10,000 revelers thronged Cambridge City Hall on Sunday night, when officials in tuxedos began taking application forms at midnight and the crowd, accompanied by a brass band, alternated between singing "God Bless America" and "Chapel of Love."

In Provincetown, a woman blew on a conch shell and a man in a dress burst into song after the town clerk announced the last couple of the day to file their intention to marry.

In Boston, a string quartet played Monday morning for a crowd of a few hundred well-wishers on the plaza in front of City Hall. A hundred yards away, about 30 protesters called for the legislature to remove the Supreme Judicial Court judges who ruled in November that the state could not deny the legal protections of marriage to same-sex couples and gave the legislature 180 days to change state law to comply.

"Where is the president of the United States and where are our religious leaders?" Yehuda Levin, an Orthodox rabbi from Brooklyn, asked the demonstrators. "There should be 1,000 religious leaders standing here today."

Bush said the "sacred institution of marriage should not be redefined by a few activist judges." His Democratic opponent, Sen. John F. Kerry (Mass.), opposes gay marriage but also opposes Bush's proposal for an amendment barring such marriages. Campaigning on Monday night in Portland, Ore., Kerry was asked if he would attend a gay wedding of someone close to him or someone who worked for him. He replied, "I would never reduce the happiness of any two people in life who find whatever way it is that they privately believe makes them happy and fulfills their needs and rewards them as human beings." Kerry added that he has previously attended a "commitment ceremony when it was a commitment ceremony."

By the end of the day, all seven gay couples involved in the Massachusetts court case had tied the knot. The lead plaintiffs, Julie and Hillary Goodridge, were married by the Rev. William G. Sinkford, president of the Unitarian Universalist Association, at the association's headquarters in Boston. "Here comes the bride, all gay with pride," about 100 friends and family members sang as the Goodridges walked down the aisle in Giorgio Armani pantsuits, preceded by their 8-year-old daughter as flower girl.

"This isn't anything anybody should be threatened by," Julie Goodridge told reporters after the ceremony. "We intend to uphold marriage as it exists today for the rest of our lives."

The vast majority of couples who applied for marriage licenses are Massachusetts residents. But town clerks reported that some out-of-state couples also filed papers, despite warnings from Gov. Mitt Romney (R) that their licenses would be considered "null and void."

After several unsuccessful attempts to stay the court ruling in recent months, Romney sought to limit its scope by invoking a rarely enforced 1913 law -- designed in part to preserve other states' laws against interracial marriage -- that bars couples from marrying in Massachusetts if their marriages would not be legal in their home states.

Somerville City Clerk John Long, who along with colleagues in Worcester and Provincetown had publicly rejected Romney's guidelines, said he took applications from at least six out-of-state couples.

Worcester's clerk, David Rushford, said that 12 out-of-state couples had filed intentions to marry there, and that he had performed a wedding for a Connecticut couple.

Edward Debonis and Vincent Maniscalco of New York City filed their intention to marry in Somerville. "We've had other opportunities, but we wanted to be part of what we consider to be civil rights history," Debonis said.

It is not yet clear how such marriages will be handled when the couples return to their home states.

New York Attorney General Eliot L. Spitzer (D) said in March that while gay marriage is illegal in New York, the state will recognize such marriages granted elsewhere. But Gov. George E. Pataki (R) said last week that he agrees with Romney that it is illegal for out-of-state gay couples to wed in Massachusetts.

On Monday, Rhode Island Attorney General Patrick C. Lynch (D) said that state law "suggests that Rhode Island would recognize any marriage validly performed in another state unless doing so would run contrary to the strong public policy of this state." His Connecticut counterpart, Richard Blumenthal (D), would not take a position. "An answer would require me to make law, not interpret it," he said.

The controversy over same-sex marriage began in 1993, when a Hawaiian court deemed a ban on gay marriage unconstitutional.

In response, at least 38 states, including Hawaii, have outlawed such unions, and in 1996 Congress passed the Defense of Marriage Act.

In 1999, Vermont became the only state to offer civil unions -- which confer similar benefits to marriage -- to same-sex couples.

After the Massachusetts court decision in November, officials in San Francisco; New Paltz, N.Y.; and Multnomah County, Ore., granted marriage licenses to same-sex couples. Each of those processes has since been interrupted.

Staff writer Philip Kennicott in Provincetown, Mass., contributed to this report.

Jon Goode, left, and Cary Raymond cheer after being married by a justice of the peace outside the town hall in Provincetown. They were among more than 600 gay couples who were married on the day that same-sex marriage became legal in Massachusetts, which is the first state to allow such unions.Hillary, left, and Julie Goodridge, lead plaintiffs in the gay marriage lawsuit, leave the Unitarian Universalist Association in Boston after being married.Tilly McMillan, right, bows her head to pray during a protest against gay marriage at the Arizona Capitol in Phoenix.