t was a beautiful day for a demonstration - sunny, breezy and just warm enough - as more than 100,000 New Yorkers took to the streets today to protest the war in Iraq.

For four hours beginning at noon, the peaceful crowd ambled, danced and marched down Broadway from Herald Square to Waverly Place and then over to Washington Square Park. The organizers of the march said that the crowd exceeded a quarter of a million; the police declined to give an official estimate.

The crowd came in many colors and flavors, and so did its moods. Some signs were prayerful or polite (``Please stop the killing''), while others employed angry expletives. Many handmade signs referred to the bomb barrage on Baghdad on Friday, like the one that read ``New Yorkers remember our own shock and awe.''

Though the march itself was peaceful, after its official permit had expired at 4 p.m., groups of young demonstrators clashed with the police on the north end of Washington Square Park.

By 6:30 p.m., 47 people had been arrested, police officials said. Someone in the crowd had released a canister of Mace, the police said, injuring 11 officers, including seven who were taken to the hospital.

New York's rally was the largest, but there were other smaller demonstrations and acts of civil disobedience across the country.

In Washington, a few thousand people marched near the White House chanting, ``This is what democracy looks like.'' Then, gesturing toward the president's residence, they shouted, ``That is what hypocrisy looks like.''

In Salt Lake City, demonstrators held a mock ``Funeral for Democracy,'' carrying coffins they said represented the death of the United Nations, civil liberties, and civilians and soldiers in Iraq.

In Chicopee, Mass., a small group of demonstrators tried to block the road outside Westover Air Force Base, which has been sending military equipment to Iraq. And at a busy intersection near the Biltmore Hotel in Phoenix, a crowd organizers estimated at 1,000 inflated 3,000 balloons, to contrast with 3,000 bombs they estimated had fallen in Baghdad.

In many places, antiwar protesters were met by at least a handful of people - and sometimes many more - proclaiming support for the war.

In Chicago, about 500 antiwar demonstrators faced 3,000 people who gathered in Federal Plaza in support of President Bush, the war and United States troops in Iraq. Most waved American flags and all chanted ``U-S-A, U-S-A'' while country music blared from loudspeakers. Several dozen Harley-Davidson motorcycles circled the plaza, sending a thunderous vibration through the air.

Clear Channel Communications, the nation's largest owner of radio stations, held a ``Rally for America'' in Fort Wayne, Ind., Charleston, S.C., and Sacramento, Calif.

At the New York march, though, tt was hard to find a voice in support of the war, and many protesters proclaimed their patriotism. David M. Johnson, 55, carried a sign that read, ``No flag is more patriotic than all this,'' with arrows pointing to the crowd around him. (Turns out he is a Manhattan advertising writer).

The marchers included plenty of the sort of people who turn up at nearly all New York protests: young women with green hair, young white menwith dreadlocks, self-styled anarchists carrying black flags. There were people complaining about the ``corporate media,'' the plight of the Palestinians, capitalism, imperialism and several other ``-isms.''

There were also a lot of gray-haired veteran protesters - and veterans who were protesters. Moses Fishman, 87, was wounded during the Spanish Civil War when he was part of the American contingent that volunteered to fight, said at today's march that he has been protesting wars since Vietnam. Back then, ``the first demonstrations very few people came out,'' he said. ``If we had this many people, imagine what we could have done.''

There were also organized groups marching under banners like ``Not in Our Name'' or ``Concerned Families of Westchester,'' 30-ish couples strolling hand-in-hand, mothers pushing strollers. One woman carried a white calla lily and sighed to herself.

Two housewives in Muslim head scarves came from New Jersey to join the march. ``Bush no listen,'' said one. ``Maybe this change something. It's difficult for the families but you know the big people don't listen to us.''

Sometimes the crowd seemed almost festive; a man was dressed in a bunny suit and stilt walkers sported Uncle Sam hats. Several people there said they were exhilarated to be part of such a large outpouring of antiwar sentiment.

Korean drums, Dixieland brass, Irish whistles, and other instruments mixed with clanging pot lids and chants of ``Peace Now!'' and ``No Blood for Oil!'' A pair of teenage girls sang ``Dona Nobis Pacem'' - give us peace.

This was the first antiwar demonstration for Sarita Martinez, 23, who carried a homemade sign reading ``Couch Potatoes 4 Peace'' (one spud was reading a soap-opera magazine). Ms. Martinez said she herself is not a couch potato - she has a full-time job as an administrative assistant and is also attending Hunter College.

Why was she protesting against the war in Iraq? ``My best friend is there,'' she said, clutching a dog tag. ``This is for him.''

Her friend Marleny Rubio, 22, had been to an earlier demonstration, in February, which was stationary because the police would not give a marching permit. Many people complained about the police's tactics at that event, especially about the barricades that kept some people away from the protest and penned in others, in the freezing cold.

The organizers of that event, a group called United for Justice and Peace, negotiated with the police and were able to get a permit for today's march. While there were barricades along the sides of the streets in midtown, people were permitted to move on and off Broadway, and there were few barricades south of Union Square.

The march ``was obviously very successful, obviously very peaceful,'' said a spokesman for United for Peace and Justice, David Lerner. ``It vindicated our right to march.''