CHICAGO (MarketWatch) — An increasing number of people began calling downtown Chicago home over the last decade or so, as new condominiums and then rental-apartment buildings accommodated all those young professionals and empty nesters interested in downtown living.

In fact, Chicago’s downtown population increased by a net 48,000 residents between the 2000 and 2010, according to a recent U.S. Census Bureau report. That was the largest numeric gain of downtown residents seen in cities throughout the country.

“Even though the market in the for-sale sector began to erode after 2005, then you had a transition into the rental sector, so [downtown Chicago] didn’t lose a beat in terms of population growth,” said Tracy Cross, president of Tracy Cross & Associates, a company that does market analysis and consulting for home-building clients, and is based in the Chicago area.

But the Second City wasn’t the only one to post impressive downtown population gains.

Metropolitan areas with 5 million or more people saw double-digit population growth rates in their downtowns during the time period, the Census Bureau reported. New York, Philadelphia, San Francisco and Washington also saw large boosts in the number of residents living within a 2-mile radius of City Hall.

“It certainly confirms what a number of us have been saying about a shift toward central urban living,” said John McIlwain, senior resident fellow at the Urban Land Institute. But, he added, the shift isn’t happening in all downtowns throughout the country.

Cities including New Orleans and Baltimore as well as Dayton and Toledo, Ohio, actually saw populations decrease in their downtowns during the 10-year time period, the Census reported.

“It’s not just about walkable, urban neighborhoods — that is a necessity, but not sufficient” on its own to get people to move into downtown neighborhoods, McIlwain said. “It has a lot to do with the economic development of the city and design and mix of the city,” from amenities to employment opportunities.

Jobs attractive to young, college-educated residents need to be in abundance in the area, and a healthy mix of services, restaurants and cultural attractions need to target not only young people but also those in their 50s, 60s and 70s, he said.

While Baltimore’s waterfront helps create an interesting downtown environment, for example, the city has failed so far to generate an economic revival, McIlwain said. More than 10,000 fewer residents lived in Baltimore’s downtown in 2010, compared with 2000.

Chicago’s downtown, on the other hand, can often beat out nearby suburbs for those looking for an entertaining lifestyle, Cross said. Unlike some places, the Chicago area doesn’t really have suburbs that meet or exceed the number and quality of amenities in the downtown area, he added. Living in close proximity to work is a draw for others.

And the housing bust is a factor that is keeping some young professionals from moving out of Chicago’s core.

“The typical buyer of condo units were singles and also 28- to 32-year-old, two-person professional households,” he said. When the couple decided to grow their family, they’d typically move to a suburban market where the schools were more highly acclaimed.

But today, with many borrowers underwater or unable to sell their homes, some of these condo-unit owners are prevented from moving on, meaning the downtown Chicago area is retaining residents who would have otherwise left by now, he said.

Racial mix of movers

The Census report also found that, nationwide, most of the growth in downtown markets has been due to non-Hispanic whites moving in to the areas.

“The Washington metro area is a notable example of this pattern,” said Steven Wilson, a co-author of the Census report, in a news release. “We see increases in the non-Hispanic white population, in both numeric terms and share of the total population, in many of the District’s census tracts in or close to the city’s downtown area.” Meanwhile, the share of non-Hispanic whites in the surrounding suburbs of Washington has decreased by 10 percentage points or more in many census tracts.

Minority population growth showed different trends, according to the Census.

The black population increased the most outside of an area’s principal city — in other words, its suburbs, the report found. And Hispanic population growth over the time period occurred most in pockets in and adjacent to the principal city’s perimeters.

“There are still fair-housing issues in the suburbs, but they are less,” and that is opening up the suburbs to more minority homeowners, many of whom are drawn to the areas for amenities such as better schools, McIlwain said.