Chicago's population decline in the first decade of the 21st century is a tale of two cities: astonishing growth downtown, decline almost everywhere else. The Loop added almost 13,000 people, growing almost 80 percent over the decade. The Near South Side added almost 12,000 people, for a 125 percent increase in population. But the vast majority of Chicago's community areas lost population: a 34 percent decline in far south-side Riverdale, 11 percent in Lincoln Square, 0.3 percent in Lincoln Park.

A few neighborhoods far from the downtown resurgence, however, are growing—the far west-side enclaves of Archer Heights, Brighton Park, West Elsdon, Gage Park, West Lawn, Clearing, and Ashburn, which added more people, overall, than the central-city growth that's garnered so many headlines.

What's happening?

"A couple people anecdotally said that they felt this southwest side area was becoming more of a port of entry than it had been in the past, perhaps supplanting some of that role that other communities have played in the past—the Pilsens, the Little Villages," says Marisa Novara, a director at the Metropolitan Planning Council who specializes in community development and housing, and who's researching the switch. "As more folks from those neighborhoods have shifted south and west, now, as they have friends and family coming, those folks are going to those neighborhoods instead."

Pilsen, of course, has long been a flashpoint for gentrification. But that's unlikely to be the whole picture, as Little Village has, for better or worse, avoided it. Instead, Novara points to the fact that the far southwest side offers much of what many people want.

"If you know Pilsen and Little Village, they're much denser neighborhoods, very different kinds of housing stock. When you get further on the southwest side, you have much more of a feeling of a single-family, bungalow-belt kind of feel," Novara says. "Particularly, if you're talking about the east side of Pilsen, you're talking about gentrification pressures, where people may be saying either, 'wow, I can't afford to live here anymore,' or 'I'd like to buy a home, and I could probably buy a lot more if I move to another neighborhood.'

"We're not seeing those same kind of indications in Little Village. But you do see it as one of the most dense in the city, and one with the least green space. So you may well see people that are saying, 'I'd like to change that dynamic for me and my family.'"

But that doesn't necessarily mean a corresponding fall in population density. In the seven neighborhoods Novara focuses on, the increase in people per household exceeded the increase in neighborhood population.

In many respects, it's a good combination. "It's said that you can attract retail if you have high incomes and low density, or you can attract retail if you have high density and low incomes," Novara says. Chicago has long struggled with retail density in its low-income neighborhoods; it fares very poorly compared with other cities in that respect, according to fascinating research by the University of Chicago's Mario Small, and population declines in many of the city's low-income neighborhoods threaten to worsen the problem.

"One of the things that we found in the southwest side research we did is that the number of families per household had dramatically increased," Novara says. "With the rise in population, people per household also rose exponentially. That's the kind of thing that, as a community, you'd want to develop some services around it, and homeownership classes, and rental supports, but I would much rather be dealing with those kinds of issues because you still have people who are demanding a certain level of services, filling your schools, working jobs, and so on. You're starting from a place of strength."

As Novara details in her piece, those supports have not necessarily followed the shift in population, as new residents of the far southwest side make the commute back to the old port of entry in Pilsen for language and job training. Schools are full, and pre-K is run in shifts. Catering to these new ports of entry could do more than just serve their residents; it could strengthen these new destinations for badly needed future residents.

"Our biggest challenge right now are neighborhoods that are severely depopulated," Novara says. "For that we need new people, not just moving around the folks we have."