Darker blue = wealthier area. Median Household Income quintiles from 2011-2015 by Nick Finio.

Our region is experiencing a 40-plus-year economic boom. We can see it, feel it, and hear it. Stories about the pressure exerted by the high cost of living in DC and its inner suburbs, particularly on longtime residents, abound—and rightfully so. This narrative reflects skepticism of rapid economic growth, as well as an assumption that it is almost entirely playing out in high-density, close-in urban neighborhoods that were once affordable. But in fact, this economic boom hasn’t been constrained by geography.

The Washington, DC, metropolitan area is consistently ranked as one of the most well-off in the country. Some rankings have even found that half of the top 10 highest-income counties in the country surround the District. These rankings typically use Census data on median household incomes at either the metropolitan or county level. So despite entrenched concentrated poverty and prognostications of an economic slowdown due to a changing economy and rapidly shifting demographics, our region is not likely to stop appearing at the top of wealth-charting listicles.

Many publications, including GGWash, often write about wealth by highlighting what it’s wrought. Groups of people are being left further behind—often ones that have been systematically disadvantaged—in the wake of economic growth that feels explosive. The disparities between the wealthy and the poor seem intractable, ever-expanding, and cruel. It is fundamentally unfair that as our region maintains and grows its wealth, many people who have been continually denied access to transit, healthcare, green space, and affordable housing are denied them still.

Today we’re taking a look at where the money is in the Washington region. Our maps illustrate where highly-resourced communities have been located over time, and how their spatial patterns have shifted.

Where the wealthy people are

Though DC’s core is dramatically inverted from the days when everyone who could afford to leave left, growth has also exploded in exurbs like Ashburn and Frederick. Inner suburbs like Takoma Park and Arlington, once considered sleepy, crunchy, and middle-class-affordable have seen property values rise considerably in just the past year. All those landscapes make up our region, and what’s happening in them factor into wealth, poverty, power, and access within DC, and outside of it.

The table below shows census-tract level median household income data for the years 1990, 2000, and 2015 (see the bottom of this post for explanations on our data source). The mapping in this post uses quintiles, or five equally-sized (by number of tracts) sections of the region, to show how census tracts have “ranked” in terms of their income, relative to the rest of the metropolitan area, over time.

For example, a middle-fifth census tract in the year 2000 would have a median household income (the median of all households in the tract) between $80,787 and $97,921. In the same year, a bottom-fifth tract would have had a median household income of between $11,137 and $62,561.

We’ve taken each tract and ranked it in the years 1990, 2000, and 2015, and mapped those rankings. You can see an animation of this below.

What do you see in the map? We notice that the region’s long-observed east-west divide has been persistent since 1990, but has shifted slightly as the region’s core, DC, has become more affluent. We also notice that high-income earners have “exurbanized.” Tracts along I-66 and the Dulles Toll Road, as well as Frederick County and southern bits of I-95, have moved up in quintiles.

Now, unfocus your eyes: High incomes have decompressed since 1990. Once tightly bunched around the center census tracts, they’re now more diffuse.

These trends exacerbate inequality

What does this mean? Most immediately, what those who live in the region will experience is that exurbanization—the expansion of people, and their wealth, to farther reaches, typically redeveloped farmland—will put pressure on our transportation networks, particularly roads. Virginia has responded to this not with investments in transit such as better bus service, but with a massive expansion of highway toll networks on I-66, I-495, and I-95. Now Maryland may do the same.

Clayton Nall’s The Road to Inequality describes how partisan attitudes have formed around federal highway spending. (You can listen to Alex and Clayton talk more about this on The Henry George Program.) His polling shows that members of both parties favor spending on highways, but only Democrats favor spending on public transit, too. Nall writes that “improved highways are likely to allow households to choose from more politically compatible neighborhoods.” Sprawl, which is facilitated by highways, can be considered both exclusionary and partisan.

There are also substantial economic and social costs to covering the distance between everything that roads create: “An implication of the existing socioeconomic distribution of automobile and transit users is that new highway infrastructure will, all else equal, expand job and housing options only for those with the resources to use the new highways,” Nall writes.

So the decompression and dispersion of people across any region will almost certainly exacerbate inequality. It costs more to travel farther distances; a higher burden of both time and cost will disproportionately impact women, people of color, and people who earn less money. And because wealthy communities are, via highway spending, federally aided in maintaining a level of exclusion, there is no reason to believe that exurbanization won’t bring with it attempts to keep people out through restrictive policies.

This doesn’t have to be our future

Regional cooperation and planning could shift exurban development—which is popular—towards transit corridors, particularly underutilized MARC and VRE station areas. Opening up development capacity in inner suburban jurisdictions, along arterial roads, and in commercial areas could pull some farther-out development back in.

Staunching the outward expansion of development is desirable not just from a redistribution-of-wealth perspective, but also from the perspective of mitigating climate change. We should be mindful that where the money is is where the exclusion is, both in center-city neighborhoods and far-flung suburbs.

Data note: Data is compiled via authors’ calculations from decennial census data (1980-2010) spatially adjusted to 2010 census tract boundaries via Brown University’s Longitudinal Tract Database. 2011 to 2015 data is from the American Communities Survey. All income numbers are inflation adjusted using CPI-U-RS to 2015 dollars. There are 1,360 census tracts in the dataset; years prior to 1990 are not included because far-flung exurban and rural tracts were not yet “tracted” by Census. The authors thank Eli Knaap, PhD, Associate Director of the Center for Geospatial Sciences at the University of California, Riverside for his work in developing the dataset.

Alex Baca is the Housing Program Organizer at GGWash. Previously the engagement director of the Coalition for Smarter Growth and the general manager of Cuyahoga County's bikesharing system, she has also worked in journalism, bike advocacy, architecture, construction, and transportation in DC, San Francisco, and Cleveland. She has written about all of the above for CityLab, Slate, Vox, Washington City Paper, and other publications.

Nick Finio is the Associate Director of the National Center for Smart Growth at the University of Maryland, College Park, where he is also a PhD Candidate in Urban and Regional Planning. His dissertation is focused on gentrification in the DC area and elsewhere. At NCSG, he works on a variety of projects, including Purple Line advocacy and various regional planning projects. He has lived and worked in the region since 2011, and currently resides in Hyattsville with his son.