The traditional weekend-long, exuberant celebration of Halloween in the heart of Georgetown will be confined to a single night this year if the District police have their way.

Last year, police estimated that more than 40,000 revelers crowded into the narrow streets of historic Georgetown and by midevening had taken over the several blocks around the neighborhood's crossroads of Wisconsin Avenue and M Street NW.

Police said they were lucky that Halloween fell on a Wednesday. This year, they fear that because Halloween falls on a Thursday it will trigger a three-day celebration into the weekend, as it has in the past.

"We are restricting Halloween to just the 31st this year," said Capt. Steve Carson, head of the police detail for Georgetown. "We have asked the cooperation of the bar owners to keep the celebration down to that one night" and have received it, Carson said.

In years past, costumed celebrants have taken over Wisconsin and M and adjoining blocks, creating one big street party, a massive traffic jam and headaches for police officers trying to control the crowd and answer calls.

Carson said this year the department will try to keep all the streets open but may yield the intersection of Wisconsin and M, if necessary.

"We will try to hold any street closings to that one intersection," he said. "On Friday and Saturday nights, we will not tolerate that type of behavior."

Mike O'Harro, owner of Champions bar and the man credited with promoting the Georgetown Halloween party scene during the past 10 years, said that he plans to cooperate with the police and limit his bar's celebration to the one night.

"I was flattered that the police department asked me some time ago which night we would celebrate," said O'Harro.

"Now they are asking for my cooperation in keeping it to one night, and we will. We will treat Friday and Saturday night like ordinary weekend nights."

Juan Cameron, president of the Citizens Association of Georgetown, said he hopes for a one-night celebration, but "only God and the P.R. people know for sure. It is not the sort of thing that the police department can dictate."

Carson said a parking ban already in effect for Friday and Saturday nights around Wisconsin Avenue and M Street will be in effect Thursday night as well. That ban prohibits street parking in the area generally from K to N streets and from 29th Street to Key Bridge from 6:30 p.m. to 4 a.m.

Four hundred officers will be on patrol in Georgetown Thursday night, Carson said. He said the officers this year will "vigorously" enforce the law that prohibits drinking in public, a misdemeanor that carries a $10 fine, he said.

The police department advises people going to Georgetown not to wear gold chains. "Last year we had about 20 robberies, and gold chains were what was taken," Carson said.