The Washington metropolitan area is home to deep poverty and extreme wealth, although the two are seldom located anywhere near each other. The above map shows as much: The blue areas, among the top 10 percent of census tracts in the region by socioeconomic status, band together in the northwest suburbs. The most distressed neighborhoods, shown in black, cluster east of the Anacostia River and just over the city limits nearby.

That picture, which comes from a new analysis and nationwide map by the Urban Institute, shows inequality in a stark new light. It is not merely an economic phenomenon but a geographic one, too. It exists not just between households at the top and bottom, but between neighborhoods a few miles apart.

Put another way: The patterns of where people live in most metropolitan areas — Washington is not unique — take the problems of inequality and make them even worse. They concentrate poverty and concentrate privilege at the same time.

Washington could, in theory, have high income inequality but low neighborhood inequality — picture a scenario where the rich, the poor and the middle class were more or less scattered around the region. In that scenario, families at the top and bottom might share the same schools, shopping districts, and public parks. But in reality, their neighborhoods — and everything that comes with them — are as different as their bank accounts. And that means that people who can't afford an expensive home also don't get access to safe streets, cleaner air and better education.

In this analysis, the Urban Institute's Rolf Pendall and Carl Hedman ranked Census tracts not just by their average household income. They constructed a single socioeconomic score that also captures the homeownership rate, the median home value and the share of people with college degrees. The top 10 percent of Census tracts do well on all of these fronts. They have high incomes, expensive houses, broad homeownership and lots of college grads. The lowest ranked tracts, conversely, do poorly in all of these ways.

The inequality between tracts at the top and bottom is particularly stark around Baltimore, Columbus, Dallas, Houston and Philadelphia. And the particular spatial patterns in these regions look familiar: Invariably, the most distressed places are in the inner city, the most affluent in the suburbs.

Here is Baltimore:

And the Dallas-Fort Worth area:

Detroit is a good example, too:

Despite all of the attention given to newly gentrifying neighborhoods and growing suburban poverty, these maps show that the predominant pattern remains the same as it's been for decades: poverty in the city and wealth in the suburbs.

Look across time, and neighborhoods at the top and bottom are remarkably stable. Deeply poor places tend to stay that way, but so do incredibly wealthy ones. And they do that by design, often through housing and zoning policies that keep out more affordable apartments and rental housing (these are the kinds of policies that Supreme Court Justice Anthony Kennedy singled out as violations of fair housing last week).

We generally spend a lot more time focusing on where the poor live, and what it means for them to live in concentrated poverty. This analysis tries to draw attention to the other side of the story: that affluence is concentrated too, often in walled-off ways that exacerbate inequality for the poor.