Displacement. We’ve read about it in the context of refugee camps and en masse exoduses from war-torn regions, but few Americans consider it a domestic problem consistently growing in scale.

But now, as American cities are complaining about the escalating costs of maintaining severely overcrowded prisons, the displacement of previously incarcerated persons has become an issue seeped in a sense of urgency.

The numbers are startling. Prison populations have risen from 200,000 in 1970 to 2,000,000 in the year 2000. Ninety-five percent of inmates return home eventually and of those that do forty percent are sent back to prison within a few years. The mass movement of people in and out of neighborhoods is costing American taxpayers big bucks - the operating expenses for state prisons is approximately $30 billion a year.

Prior research into this issue using traditional methodologies has resulted in sweeping generalizations and band-aid solutions that fail to proactively address the root causes of crime in individual communities.

In an effort to localize the growing problem, Laura Kurgan, an architect and professor at Columbia University’s Graduate School of Architecture, teamed up with Eric Cadora, David Reinfurt, Charles Swartz, and Sarah Williams embarked on a project to map the migration patterns of previous and current inmates in twelve cities across the country.

The team figured out the prison cost of every block in the city by multiplying each prisoner’s minimum sentence by their annual prison fees, then finding the sum of these two figures. Enter million dollar blocks, individual census blocks where residents being sent to, released from, and sent back to prison cost the city about a million dollars a year each.

Using GIS and other technological innovations, the Spatial Information Design at Columbia and the Justice Mapping Center mapped their findings in  Million Dollar Blocks. Using databases of incarcerated city residents not available to the public, the team created visual depictions of what they call prison geographies. They found that in the urban settings they studied, crime was densely concentrated in a few neighborhoods, with prison geographies intersecting  with geographies of poverty and neighborhoods of color.

This results not only in over dependence on the existing criminal justice system, but to flaws embedded in the system itself a system willing to spend an exorbitant amount of money on revolving-door incarcerations, but not willing to consider ways of addressing these ills at their core: in the neighborhoods.

In the video above, Kurgan reveals the project’s conception and findings.