There are neighborhoods on the West Side of Chicago where nearly every block has been painted red — a sign, on the above map, that someone there was sentenced to time in an Illinois state prison between 2005 and 2009 for a nonviolent drug offense.

On several dark-red blocks, the missing residents are so many — or their sentences so long — that taxpayers have effectively committed more than a million dollars to incarcerate people who once lived there.

This is the perverse form that public investment takes in many poor, minority neighborhoods: "million dollar blocks," to use a bleak term first coined in New York by Laura Kurgan at Columbia University and Eric Cadora of the Justice Mapping Center. Our penchant for incarcerating people has grown so strong that, in many cities, taxpayers frequently spend more than a million dollars locking away residents of a single city block.

In Chicago, Daniel Cooper, Ryan Lugalia-Hollon, Matt Barrington and the civic technology company DataMade have reprised the concept for one of the most divided cities in America. By their count, there are 851 blocks in Chicago where the public has committed more than a million dollars to sentencing residents to state prison for all kinds of crime. The total tops a million dollars for nonviolent drug offenses alone in 121 of those blocks.

Those places, tracing the city's segregated history, are clustered in neighborhoods on the South and West Sides. These patterns, the project points out, mean that most of Chicago's incarcerated residents come from and return to a small number of places. And in those places, the consequences of incarceration on everyone else — children who are missing their parents, households that are missing their breadwinners, families who must support returning offenders who are now much harder to employ — are concentrated, too. This map shows where those communities are clustered on the West Side, relative to the North Side of Chicago:

The North and West Sides of Chicago.

These numbers refer not to yearly expenses but total investments. The Illinois Department of Corrections spends about $22,000 a year per inmate. This project multiplied that figure by the minimum sentences given to each offender sentenced between 2005 and 2009.

So these totals are likely an underestimate. They don't reflect the public money spent to incarcerate people sentenced to state prison from these same neighborhoods before 2005 or after 2009. And they don't reflect public money spent sending people to federal prison, or locking them up in local jails while they await trial.

Million-dollar blocks exist too in New York and New Orleans and many big cities. From the original Spatial Information Design Lab project in New York that pioneered the concept:

Spatial Information Design Lab

When the spatial concentration of all this money is mapped so starkly, the picture poses a critical question: What would happen if we poured the same resources into these same struggling parts of any city in very different ways?

What if we spent $2.2 million dollars not removing residents from the corner of West Madison and Cicero but investing in the people who live there? What if we spent that money on preschool and summer jobs programs and addiction treatment? Evidence suggests that such investments could do more to deter crime than locking people away.

"People hear that there’s a very big violence problem in Chicago, but nobody’s really talking about the drivers of it," says Cooper, the co-executive director of the Institute for Social Exclusion at Adler University in Chicago. "They're talking about the individuals who take part in shootings. But nobody’s asking the question, 'why are there shootings in the first place?' What’s further upstream? What are the bigger determinants of this problem?"

Why do we willingly spend so much money imprisoning people, while we have bitter political fights over smaller sums that would educate children or feed their families or help people stay out of prison?

"Incarceration is held to a completely different standard," Cooper says. "The evidence base doesn’t support its use. But the notion that people need to be punished and removed from their communities is so pervasive."

Lugalia-Hollon recalls that he didn't realize himself that incarceration was a neighborhood problem — even a problem of race and social justice — until he took a job a decade ago in the North Lawndale neighborhood on Chicago's west side. There, 70 percent of the men between the ages of 18 and 54 are likely to come in contact with the criminal justice system.

"The country’s at a point where it’s starting to wake up to this," says Lugalia-Hollon, who now runs a youth development network in San Antonio. "Some of that is fiscally motivated, which is okay. But if folks look at the Web site and just say, 'Oh man, we’re wasting dollars,' they’re not getting the whole story. We’re also wasting lives. We’re losing communities. We’re losing families."