Officials of the Archdiocese of New York, one of the city’s largest property owners, expect to sell off a significant number of church buildings, schools, and charitable facilities in the next year, to compensate for shifts in Catholic population concentrations, a church spokesman said yesterday.

“We are going through a process of realignment that will very probably result in the sale of property in Manhattan, the Bronx, and possibly Staten Island,” the communications director for the archdiocese, Joseph Zwilling, told The New York Sun. “We will also look to add parishes in Rockland, Dutchess, and Orange counties where the Catholic communities have expanded.”

The timetable includes deciding which parishes and facilities will be closed or merged with existing parishes within the next three to 12 months, followed by several weeks or months of transition before the real estate will be put on the market, Mr. Zwilling said.

“Once the announcements are made, there will be a transition period for the plans to go into effect,” he said.

The New York archdiocese encompasses 10 counties and 413 parishes, with 99 parishes in Manhattan, 68 in the Bronx, and 35 in Staten Island. It does not include Brooklyn and Queens, which, with Nassau and Suffolk counties, come under the auspices of the Diocese of Rockville Centre.

Speaking of the New York archdiocese, Mr. Zwilling said: “Manhattan has 25% of the parishes, but certainly not 25% of Catholics.” He said the borough is home to only about 10% of the Catholics in the Archdiocese of New York.

In Putnam, where 80% of residents are Catholic, according to a 2000 census released by the Glenmary Research Center in Nashville, Tenn., there are only five parishes. Orange County has 29 parishes, and Rockland has 18, according to the archdiocese’s Web site.

At Staten Island, however, overdevelopment in the borough has caused the Catholic demographics to change, according to Mr. Zwilling. “It is just as likely that we will be opening another church as closing one,” he said.

The archdiocese began examining the parishes to realign them more than a year ago, but the project was shelved after Bishop Timothy McDonnell, who had been in charge, left to become bishop of Springfield, Mass., according to the spokesman. It was restarted in earnest at the beginning of this week under Auxiliary Bishop Dennis Sullivan, who was ordained by Cardinal Egan in September and began working full-time at the archdiocese on Monday.

As Catholic congregants have been moving farther north, the archdiocese has steadily been closing parishes in neighborhoods that cannot sustain them. That includes places such as Harlem and the East Bronx, where many empty churches can be found, according to a real-estate broker with Penson Companies, Frank Farricker.

“There used to be a large Italian community in East Harlem with many incredible churches that are now largely empty, and the church has started to sell some of them to developers,” Mr. Farricker said. “There are also giant swaths in the Bronx where you can see several Catholic churches that have been closed. We have been wondering for some time what they would be doing with those properties.”

In Boston, Catholic church officials, faced with immense expenses in connection with settlements of lawsuits alleging sexual abuse by priests, are selling off large real-estate holdings. Sources familiar with the situation in New York said that the likely property sales here are unrelated to suits alleging clerical misbehavior.

The total market value of the archdiocese’s properties is in the billions of dollars.

The archdiocese is not the only religious group in the city that is shedding some real estate.

Collegiate Church, a Dutch Reformed congregation, is in the midst of a five-year plan to reposition its real-estate holdings. According to a report in the New York Post, it is in the process of selling a parcel at the corner of 67th Street and First Avenue for $300 to $400 a square foot, or $39 million to $52 million for the 130,000-square-foot plot.

Also being sold is the Washington Square United Methodist Church in Greenwich Village, for $13 million, or $810 a square foot.

“While it is zoned for residential, it’s a long shot that it would be converted into condominiums,” the listing broker at Massey Knakal Realty, James Nelson, said. A theater group or a school is the most likely buyer, he said.

As for the Catholics, they say that while the process they are embarking on will result in real-estate deals, it will not leave any of their congregants without a house of prayer.

“There are a number of criteria we are considering, and we will not leave people without a church,” Mr. Zwilling said. “What we hope is that if there are two churches in a single area, to combine them to strengthen the parishes and the sense of community there.”

No dollar figure was available for how much the real-estate sales could generate for the church, Mr. Zwilling said. “Money is certainly an issue because this is the real world,” he said, “but it is not the only issue.”