Howard County Executive James N. Robey was just a rookie policeman when developer James W. Rouse began building Columbia into the "Next America," a grand experiment in planned community living that became a bedrock of the Washington area's suburban growth.

Thirty-seven years later, when told of the impending sale of Rouse Co. to a Chicago developer, Robey froze. Imagine Detroit without General Motors, Florida without Disney.

"I just sat there for 30 seconds looking at the message handed to me, saying: 'Is this real?' " said Robey, who was hobnobbing with fellow politicians in Ocean City when his aide handed him a note about the deal. "We shared this adventure called the growth of Howard County. . . . I am just shocked."

While there has been plenty of speculation about Rouse Co.'s possible departure from Howard County in recent years, yesterday's deal with General Growth Properties Inc. appeared to be a well-kept secret, even among the financial analysts who most closely track the firm.

But within hours, shock among the region's political and civic leaders gave way to unease as they tried to fathom the likelihood of losing the headquarters -- and some or all of the 200 jobs housed there -- of an institution revered for decades as one of America's most innovative residential and retail developers. The company helped reinvigorate Baltimore with its Harborplace development in the 1980s and pioneered the now-ubiquitous food court. Its influence can be felt in many of the planned communities that ring American cities.

Immediate attention turned to the future of the company's charitable giving, such as its recent gift of $350,000 to construct a building for the arts at Howard Community College.

Will that sort of philanthropy dwindle?

Then there are the development projects hanging in limbo: undeveloped land in Town Center near Merriweather Post Pavilion, and even more land at Emerson, one of two major new housing and commercial developments in Howard County.

"None of those issues are probably even on the radar screen of the new owners," said Richard W. Story, chief executive of the Howard County Economic Development Authority.

"The owner has huge assets outside of Maryland. Merriweather Post Pavilion may not be the first thing they look at."

By yesterday afternoon, financial analysts described the deal as good for shareholders. But "Not Good for Baltimore," declared the title of a report, written by analyst David M. Fick of Legg Mason Walker Wood, which predicts that General Growth will substantially restructure Rouse Co.'s "bloated infrastructure."

After the announcement, Anthony W. Deering, Rouse's chief executive, made courtesy calls to local leaders, trying to allay fears in "measured tones," according to some who spoke to him.

In an interview yesterday, Deering said General Growth will contribute a one-time, $20 million payment to the Rouse Co. Foundation, the company's independent philanthropic institution. Armed with the new money, the foundation will continue to operate even as the company that created it disappears, Deering said.

Some civic leaders said they understood the thinking behind Deering's decision.

"Given the condition of the real estate market, he needed to either grow, or be part of a group that did grow, to give [Rouse] leverage in a consolidating industry," said Bart Harvey, chairman and chief executive of the Enterprise Foundation, launched in 1982 by James Rouse to invest in inner-city neighborhoods and provide housing to low-income people nationwide.

"But it hurts," Harvey said. "The loss of a major, progressive, outreaching company like the Rouse Co. is a real loss."

But many who track Rouse Co. say it long ago ceased embodying the spirit of its founder as it evolved into more of a bottom-line operation that came to be known in some circles for high rents and that sometimes angered retail tenants.

Joshua Olsen, author of the recently released "Better Places, Better Lives: A biography of James Rouse," said the company has slowly diminished its involvement in Columbia over the past several years.

For instance, within the past year and a half, the company sold Columbia's village centers, a series of community enclaves created to resemble the village green of old New England towns, a place for people to gather and socialize.

When it sold the villages, the company essentially gave up "the last day-to-day connection between the Rouse Company and Columbia," Olsen said.

"The villages really don't mesh with what the Rouse Company has become."

Rouse owns almost 40 large regional malls, and "these small village centers did not fit into that portfolio of companies," Olsen said. The company has been emphasizing glitzy, upscale developments, such as the Fashion Show mall in Las Vegas, and selling its more modest, mid-quality malls.

It is still best known for developing urban renewal projects such as Faneuil Hall in Boston and Harborplace in Baltimore's Inner Harbor.

While General Growth will no doubt carefully sift through that portfolio, closer to home many will be wondering about the fate of Rouse's contemporary office building, set on Columbia's lakefront and designed by architect Frank Gehry.

If the company moves out, "who will continue and complete parts of Columbia that are open for development?" asked Robert Tennenbaum, director of real estate development for the University of Maryland's Baltimore campus. Tennenbaum spent seven years working with Rouse in the mid-1960s while Rouse pieced together the parcels of farmland that became Columbia.

Several parcels of undeveloped land remain in Columbia's downtown, or Town Center, as it is known. They are zoned for development, including a 51-acre parcel next to Merriweather Post Pavilion that has recently been the subject of controversy.

The county's zoning board this year rejected a company proposal that would have increased Columbia's housing density and resulted in about 1,600 new housing units next to the outdoor concert hall.

The company also is proposing commercial and retail development on the land where it had originally sought the 1,600 housing units. Whether the sale to General Growth will affect that plan is unclear.

Pearl Atkinson-Stewart, a Columbia resident for 30 years and a member of the Columbia Association's council, said she, like almost everyone she knows in Columbia, was surprised by the news. And yet there was a sense of inevitability about the company's departure from the community, she said.

"I think we knew that one day this was going to happen. We just didn't think it was to be so soon," Atkinson-Stewart said.

Staff writers Neil Irwin, Terence O'Hara and staff researcher Richard Drezen contributed to this report.

Rouse created Columbia's village centers, a series of community enclaves meant to resemble the village green of old New England towns.