In 1970, two-thirds of Americans lived in middle-income neighborhoods, according to the US2010 research project. Now it's less than half, and the proportion of poor and rich neighborhoods has doubled. On the map to the right, you can watch middle-income neighborhoods (the lighter colors) be gobbled up by the red (affluent) and blue (poor) neighborhoods over time.

It's not just that rising income inequality is depleting the middle class that would fill those middle class neighborhoods, according to Sean Reardon, one of the US2010 researchers who provided us the maps. Americans are sorting themselves by income more than ever.

Today, we'll explore income segregation with Reardon and with Jennifer Arndt Robinson, who has decided to stay in a neighborhood near Patterson Park even though her family could afford to "move out to the county." We'll also visit a neighborhood in Northeast Baltimore that is holding on to its middle-income status--but just barely--and talk to residents Sheila Ebelein and Demetric Farmer.

First up in this episode is an essay from Maryland Morning senior producer Lawrence Lanahan about income inequality in Maryland--and why it's taken our series four months to start exploring it.