CLEVELAND, Ohio -- When a new job brought Stacey Brown to Cleveland from San Francisco two months ago, she went looking for an apartment downtown. Her manager told her that's where young people were flocking. Sure enough, she found a full house.

"It was soooo hard finding an apartment," said Brown, an upbeat and single 26 year old. "I mean I looked for three weeks, all over downtown."

The hunt was worth it. She found an opening at The Residences at 668 Euclid on bustling lower Euclid Avenue. Soon, she was meeting new friends over beers at Winking Lizard and tapping into the free Wi-Fi at Colossal Cupcakes.

"It's hard not to like it," said Brown, a medical-device saleswoman for Stryker. "Clevelanders are such great people. It's that Midwest charm. And the restaurants are phenomenal."

When she joined the downtown scene, she helped to swell what's shaping into a historic migration. Twentysomethings are creating a new and potentially powerful housing pattern as they snap up downtown apartments as fast as they become available.

Thanks largely to young professionals, the inner city is growing faster than the outer city and the county for the first time in modern history, a recent Case Western Reserve University study found.

Neighborhood life is blossoming on blocks once dominated by office workers and commuters, and people are clamoring for dog parks.

Richey Piiparinen, a researcher for Case's Center on Urban Poverty and Community Development, sees a more powerful force than a casino or a medical mart.

"It's a youth movement," he said. "This could be a huge thing."

Not to say anyone will mistake downtown Cleveland for Chicago. Even after two decades of unprecedented growth, the population within walking distance of Public Square approaches only 10,000 people (compared to 29,000 in Chicago's Loop). Many urban planners see 20,000 to 25,000 residents the threshold for creating a natural, self-sustaining downtown neighborhood, one that attracts grocery stores and schools.

Meanwhile, the newcomers are too few to offset a larger exodus. Cleveland lost 17 percent of its people last decade as nearly one in five residents left the city.

Still, there are several facets to the downtown renaissance that researchers find striking. First off, a rising center city bucks the trend in a region accustomed to relentless sprawl.

Secondly, the ripples are spilling into other neighborhoods. The lure of downtown, coupled with a tight rental housing market, is sending people into Tremont, Ohio City and even Asiatown, Piiparinen believes. All three inner-city neighborhoods enjoyed stable or growing populations last decade.

Finally, look who's coming. People between the ages of 21 and 34 make up the largest share of downtown residents. Many of them grew up in a suburb of Northeast Ohio, then moved to a neighborhood their parents would never have considered.

"Do we have a generation that's really doing the opposite of its parents, going back to the center?" asks Piiparinen, who conducted the downtown population study for The Urban Institute. "It's the creative class. They're more entrepreneurial. They're mobile. They're more educated than their parents."

They're stoking a subtle, long-term trend.

Looking at a 70-year trendline, Piiparinen found that the population of Cleveland's inner city stabilized in 1960 and has trended steadily upward since. That's in contrast to the city's outer, family-oriented neighborhoods, where population fell sharply after 1990, while the suburbs also declined.

For the last twenty years, he found, the inner city has been growing at a faster rate than the Cuyahoga County suburbs and the five-county region.

Meanwhile, anecdotal evidence suggests downtown's growth is quickening. Apartment vacancies are scarce and building managers are working from waiting lists.

The new urbanites include Joe Baur, a freelance writer and the creator and host of an online satirical news show, "Mildly Relevant News." It airs thrice weekly on YouTube, the broadcast medium of his generation.

Baur, 25, grew up in Mentor. When he resolved to move back to the region from Chicago last summer, he toured a neighborhood he had seldom experienced.

He said he was surprised to discover a tribe of people like himself moving through the Gateway and Warehouse districts. He saw young professionals picking up ready-made meals at Constantino's Market, working out at the 24-hour Titan's Gym, and hopping onto the Healthline for rides to work.

"Cleveland was very, very foreign to me," Baur said. "I had only come downtown for baseball games."

Now he seldom leaves the city center and when he does it's by bus or cab. He sold his car.

"I know I'm never going to leave Cleveland," he said.

The data suggests he'll change his mind.

Downtown's population nearly doubled from 1990 to 2010, to reach 9,098 people, Piiparinen found, and young adults drove the growth. Between 2000 and 2010, he said, more than 2,000 people younger than age 25 moved into the neighborhood.

They joined a community nearly devoid of people in their 40s. By the time someone turns 35, they are likely living elsewhere, the data shows, suggesting the neighborhood has limited appeal.

"The exodus of the child-rearing age group may neutralize the gain made with the young," Piiparinen warns in his report.

He suspects the city needs to offer a broader range of amenities, including a quality elementary school and safer streets, to create a stable neighborhood.

Others say not to worry. Jim Russell, an economic geographer specializing in the demographics of Rust Belt cities, says a more diverse neighborhood may develop naturally. He suspects older folks and families will be more willing to move into a downtown astir with young professionals.

Meanwhile, the current rate of churn indicates twentysomethings will replace the departing thirtysomethings.

"I think, for the most part, age doesn't matter," Russell said. "What you want is more people downtown. That will attract other demographics. People will feel safer."

After a 2010 census filled with bad news, he said, Clevelanders should enjoy the good tidings.

"There's a hidden brain gain going on," Russell said. "Not only is your inner city growing, but it's clearly because of an influx of young adults. You're trending in the right direction."

Follow Robert L. Smith and his economic development news on Twitter @rlsmithpd.