There are more than 3,000 counties in the U.S. Of the 75 with the highest incomes, 44 are located in the Northeast, including Maryland and Virginia. The corridor of metropolitan statistical areas that runs from Washington, D.C., through Baltimore, Philadelphia, New York and Boston includes 37 of these top-earning counties (where the median family takes home at least $75,000 a year). Zoom in to the region, and it shows a kind of wealth belt unmatched even on the West Coast.

Poverty is similarly concentrated in the American South. Seventy-nine percent of the poorest counties in the country (where the median family makes less than $35,437) are located in the South:

2012 Poverty rate of the total population by county. via Atlantic Cities

This latest Census release also slices data by school district, revealing the below picture of poverty rates by district among school-aged children 5 to 17. In dark blue, these are the school districts with some the steepest challenges educating low-income children on scarce resources: 2012 school-aged poverty rate by school district. via Atlantic Cities

Relative to 2007, 33 percent of all U.S. counties saw statistically significant increases in poverty by 2012 (across all age groups), deepening the challenges in places that had been struggling even before the recession. Over this same time period, however, one part of the country in particular saw an actual increase in median incomes, and it wasn't the traditionally wealthy Northeast corridor.

It was the Upper Great Plains. Statistically significant increases in median income, from 2007-2012, are shown in green:

Change in median household income, 2007-2012, by county. via Atlantic Cities As a result of the energy boom in the Dakotas, households in about half of the counties there were better off in 2012 than they were in 2007, a distinction most of the rest of the country doesn't share.

All maps, based on U.S. Census Bureau Small Area Income and Poverty Estimates, are courtesy of the Census Bureau.