America's downsized cities (© Skip Peterson/AP)

Detroit ranks No. 4 on the list of downsized cities in America. © Skip Peterson / AP

In a way, it's the same old story: The Rust Belt, composed of blue-collar cities where manufacturing industries once dominated, can't seem to find a way to thrive.

Take Pittsburgh. Despite the fact that the city's steel industry began to deteriorate all the way back in the 1970s, the city is still better known for its mills than for its $10.8 billion stake in the technology and life-science sectors, including companies such as Bayer, BPL Global and Plextronics.

Same goes for Buffalo, N.Y., once a great producer of steel and automobiles. The city's bioinformatics research industry is flourishing, but, just like Pittsburgh, Buffalo is shedding population.

To be direct: If Bruce Springsteen, Billy Joel or John Mellencamp has written a melancholy song about your city, it's probably on this list.

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And that's the problem. General perceptions of these Rust Belt cities — that they're backward, dilapidated and cultureless — are often too harsh. And that's why, over the last decade, these areas have seen the biggest decreases in population, according to the U.S. Census Bureau.

"Reputations die hard," says Kathryn Foster, director of the University at Buffalo Institute for Local Governance and Regional Growth.

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The plight of these cities is double-edged. A lackluster reputation often keeps potential newcomers away, while young adults born there tend to flee because of a lack of a diverse range of opportunities. However, many of those born and bred in the area do return when it’s time to "settle down," Foster says.

Yet Sean C. Safford, a business professor at the University of Chicago and author of “Why the Garden Club Couldn't Save Youngstown: The Transformation of the Rust Belt,” says that it has a lot more to do with an area's business infrastructure than its "ick" factor.

Youngstown, Ohio, for example, "had an economy that basically grew up in another era," he says. When the steel industry began its decline in the 1970s, Youngstown moved on to another failing industry: autos. The few companies that have adapted to the new economy have kept globally competitive by outsourcing, which is good for their finances but bad for Youngstown.

Behind the numbers
To determine America's downsized cities, Forbes used 2008 population estimates for the 125 largest metropolitan statistical areas in the U.S., released in March 2009 by the Census Bureau. Forbes compared those estimates with 2007 population estimates to determine the percent change year-over-year. Then we looked at the percent change in population from 2000 to 2007. Forbes combined those two rankings — weighting down the more relevant 2007-2008 percent change — for a final ranking.

While migration has slowed in general, these metro areas saw an actual decrease in population, whereas others stayed flat or continued to grow, if at a slower pace.

The state that's suffering the most is Ohio.

Topping the list is Youngstown, which, like Pittsburgh, suffered from the decline of the steel industry and never fully recovered. Dayton, Ohio, is similarly depressed: Late last year, one of its biggest employers, General Motors, shut down its plant in the city. In Toledo, Ohio, the unemployment rate is 9.8% (the national average is 8.1%), and manufacturing jobs decreased by 16% in January 2009 compared with January 2008.

And while the economy in Cleveland is diversified — from the Cleveland Clinic to NASA's Glenn Research Center to the headquarters of paint and building-supply company Sherwin-Williams — it's not viewed as a shining star of the Midwest.

But Youngstown has it the worst, seeing the biggest population declines: a 0.8% drop from 2007 to 2008 and a 5.4% decrease from 2000 to 2007. Next was Flint, Mich., with a 1.2% drop from 2007 to 2008 and a 0.3% decline from 2000 to 2007.

On the bright side
Some metro areas, like Detroit, which is ranked fourth, and Flint (both of which continue to experience devastation as the U.S. automobile industry collapses), have enough systemic problems to continually drive their populations away. But other cities on the list do possess a few oft-overlooked bright spots, indicating that negative perceptions keep new residents from coming as quickly as others leave.

In Youngstown, local officials have established the Youngstown Business Incubator, a nonprofit organization partially funded by the state government that aims to accelerate the growth rates of local tech startups.

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But these positive notes can help only so much. Foster, whose job is to come up with business strategies to further develop Buffalo, says that what these areas really need is better marketing.

"When I moved to Buffalo, I carried the same misconceptions that most do. What I found was jaw-dropping" she says of the city's architecture and cultural offerings. "Efforts to market the region are so important."

But Safford says it goes further than that. "It's about competitive companies," he says. "We'd all like to think that Seattle is popular because it's cool, but come on, it's because of Amazon and Microsoft: companies that generate cash. They're not stuck in the past."

America’s top 5 downsized cities

1. Youngstown, Ohio

2. Flint, Mich.

3. Cleveland

4. Detroit

5. Dayton, Ohio

Click here for the full slide show of America’s downsized cities.

This article was written by Lauren Sherman for Forbes.