One Sunday morning last month, Mary Denney's two-bedroom Columbia townhouse was posted for sale on the Internet. Within hours, she got her first offer.

Denney, 50, an information management specialist, thought it would take at least two to three weeks to sell her 1,300-square-foot Town Center home, which she bought for $101,000 in 1996. But she didn't even have to hold an open house before bids rolled in. This week, Denney closed the sale for $164,000.

"I was one of the lucky ones," said Denney, who added that she knows of some Howard home sellers whose properties, particularly larger houses, have stayed on the market for weeks. "We were very surprised."

Real estate agents across Howard County reported that demand -- buoyed by basement-low mortgage rates and the county's quality of life -- is still high for a limited supply of houses. Last month, there were 404 homes sold in the county, a 15.1 percent increase over October 2001, according to Metropolitan Regional Information Systems Inc., a Rockville real estate listing service.

But agents say the sales activity, particularly among more expensive homes, is slowing down now with colder weather and the holidays approaching.

"It's still a seller's market, but the activity is not as great as it was in the late spring and summer of this year," said Al Cooke, an agent with Coldwell Banker Residential Brokerage in Columbia.

One thing that has not slowed is the climb of Howard's home prices. The county's average sale price for houses rose 13.4 percent in October to $263,324, from $232,175 a year earlier. That compares with $188,245 for the Baltimore region, $248,052 in Anne Arundel County, $178,031 in Baltimore County, $174,714 in Prince George's County and an average of $96,441 in the city of Baltimore.

Some counties, such as Fairfax, Montgomery and Loudoun, ranked higher than Howard, with average sales prices of $316,191, $322,140 and $303,773, respectively.

Mortgage rates, which dropped to a 5.74 percent average for a 30-year fixed mortgage this month, continue to fuel sales across the region, industry experts said.

"Given the near-term outlook for interest rates, the market for home sales is likely to remain quite strong for the balance of the year and into the early months of 2003," said Anirban Basu, chief economist at Towson University's Regional Economic Studies Institute, which tracks the Washington area's economy.

"One might expect to see Howard County actually underperform other jurisdictions because of losses in the stock market and job losses among white-collar professionals, but, despite that, Howard County's market has remained strong," he said.

Some agents said a reduction in activity this winter may mean a larger inventory and will allow buyers to demand houses in tip-top condition.

Suzi Padgett, branch vice president of Coldwell Banker Residential Brokerage in Columbia, said that higher priced properties, not in top condition, are staying on the market a few weeks longer. "The market has turned enough whereas buyers are expecting that at least some repairs be made," she said.

Denney heard that some other home sellers had had trouble selling their houses quickly, and she wanted to make sure her home could compete with similarly priced properties. So before listing her townhouse, Denney spent about $200 professionally cleaning her carpets, repainting some of the rooms antique white and cleaning up her yard.

"People had been telling us horror stories," Denney said. "Some [houses] were sitting and sitting."

Bob Chew, an agent for Coldwell Banker in Columbia along with his wife, Ronna Corman-Chew, said more inventory has translated into fewer bidding wars.

"Having a few more properties on the market I think is healthy on both the buyers and sellers' side," Chew said. "A lot of the buyers and sellers that we're working with now are already thinking with a January time frame. There's not as much urgency."

Still, Chew's wife said the market is brisk enough that the couple has resorted to the phone directory to call potential home sellers in certain neighborhoods in an effort to match them with buyers.

"We're kind of like a dating service -- we match up the right family with the right house," Ronna Corman-Chew said.

Melvina Brown, an agent with Re/Max Columbia in Ellicott City, said she and her husband, Rochell, also an agent, recently sent out a few hundred postcards to homeowners hoping to locate houses for their clients. Mid-priced homes, such as an $125,000 townhouse or houses starting at $100,000, are more difficult to find in the county. Newer homes can start at more than $700,000, she said.

"There's more demand than there are houses," Brown said.

Over the past five years, an average of about 2,000 housing units a year have been built in Howard, according to the county's Department of Planning and Zoning. But new construction has slowed considerably amid new growth limits imposed by the county. Last year, 1,527 residential building permits were issued, down from 2,265 permits in 2000. From January to September of this year, a total of 1,323 building permits were issued -- 869 for single-family detached houses, 289 for townhouses and 165 for apartments.

Charles Lewis, division sales manager for Patriot Homes of Columbia, one of the Baltimore region's largest home builders, said demand still exceeds the supply in Howard. Furthermore, a shortage of land that can be developed has prompted builders to turn to other counties, he said.

"The availability of [Howard] home sites is down," Lewis said. "As far as activity and desire, that's still at a very good pace."

Construction workers build single-family houses during July in Ecker's Hollow, a new development in Columbia.