How Suburbs Swung the 2020 Election

The urban-rural divide is becoming the urban-suburban divide.

By Richard Florida, Marie Patino and Rachael Dottle

November 17, 2020, 1:00 PM EST

America’s political map is famously divided into shades of red and blue. But while most of America was anxiously watching screens and needles to see which hue the handful of crucial swing states would turn, the nation’s future was ultimately being decided at a far more granular scale—in the suburbs.

Geography’s defining role in how Americans vote has increased over the past decade or so, as people have sorted themselves by income, education and ideological outlook. More affluent and college-educated professionals and knowledge workers have clustered in larger cities, as many working-class people moved outward to the suburbs and rural America, widening the chasm between blue cities and red outlying areas.

But in the 2020 presidential election, it was the suburbs that were the inflection point, carrying the Democrats to victory. The dominant fissure was not between urban and rural voters but between suburban and rural voters. And not just close-in highly urbanized suburbs in close proximity to the urban center, but some further out suburbs, even exurbs.

Overall, Democrats gained the most in the suburbs, which shifted from majority Republican in 2016 to majority Democrat in 2020, according to a Bloomberg CityLab analysis of data as of Nov. 16 for some 2,822 counties, which make up nearly 90% of all U.S. counties. These prevalent American communities went for President-elect Joe Biden by 51.2%, compared to 47.2% for Hillary Clinton in 2016, based on a classification of the suburbs from the Centers for Disease Control’s (CDC) National Center for Health Statistics. Unfortunately, there is no consensus definition of what is and is not a suburb. The CDC defines them as counties outside the urban center of large metro areas with more than 1 million people. But even considering other variations, we found that the suburbs were the hinge point of the 2020 presidential election.

The chart below divides counties according to the CDC’s National Center for Health Statistics classification scheme, which breaks out six different types of urban, suburban and rural areas. It shows how the margins between the Democratic and Republican presidential candidates changed between 2016 and 2020 in each type of county. In all but rural counties, these margins shifted in favor of Democrats in 2020. The change was most significant in the suburbs, where the margin shifted in favor of Democrats by 4.3 percentage points. Rural areas remained reliably red, and Trump picked up more ground there (1 percentage point) versus 2016. Several other types of communities—mid-size cities, small towns and very small towns—also remained majority Republican, but Democrats gained ground in each. In mid-size cities, the Democratic share of voters grew from 44.4% to 48.1%. Biden also gained slightly in large urban centers that have long been Democratic strongholds, with the margin of victory increasing slightly by .7 percentage points (although only about 71% of these counties have reported full results as of publication).

The central political role of the suburbs is not new. Suburbia has long been the key battleground for the presidency. Back in the early 1970s, political strategist Kevin Phillips famously identified the “silent majority” of conservative-leaning suburban voters. And this is likely why Trump put attracting suburban voters at the center of his own failed electoral strategy.

But Trump was relying on outdated stereotypes about the suburbs, which have changed markedly in their demographics since Phillips’ diagnosis. The suburbs are not monolithic and don’t conform to the largely white middle-class ideal of the 1950s and 1960s. They have grown increasingly diverse by race, ethnicity and socio-economic class.

Nearly a decade ago, University of Southern California political scientist Jeffrey M. Sellers identified a particular type of suburb as key to presidential elections. He called attention to more economically distressed suburbs, typically located closer in toward urban centers, which play an outsize role every four years. These economically challenged close-in suburbs were big factors in Obama’s wins and even bigger factors in Trump’s surprise 2016 victory. And as Sellers showed back then, turnout favors the Democrats. Biden surely benefitted from this year’s record turnout.

The suburbs shifted in a new and different way this cycle. Biden not only took the urban suburbs that align with Sellers’ definition, he gained even more ground in further-out middle suburbs and exurbs.

While the distinctions between these kinds of suburbs can be hard to capture, we use a few different metrics to zero in on them. The chart below arrays the 2020 presidential vote according to the types of places in Dante Chinni’s American Communities Project, which uses 36 variables to classify American counties into 15 groups of people with shared characteristics. Several of these groups are primarily suburban in character, but a few others straddle the line between urban, rural and suburban.

What is most evident is the dramatic shift in the exurbs, areas further from urban centers with high levels of education where a large chunk of the voting-age population lives—11%, according to the American Communities Project. Even though the exurbs still skewed Republican overall, they turned blue at a far higher rate than most other kinds of places. “Driving that shift in the exurbs may be the same factor driving the shift toward the Democrats in urban suburbs – high numbers of bachelor’s degrees,” wrote Chinni in an analysis of the 2020 election. “Polling data over the last decade has shown voters with a college degree are increasingly breaking Democratic.”

The Democrats also picked up considerable ground in college towns, which rank among the nation’s most highly educated places, and military posts, many of which are suburban in character. These shifts align with those in the 2018 midterm elections, based on CityLab’s Congressional Density Index, which identified a swing of further-out and sometimes more sparsely populated suburbs toward the Democrats. On the other hand, Hispanic centers, characterized by high percentages of Hispanic residents, gained the most ground for Trump, a surprising shift that political scientists will likely be unpacking for years to come.

We can see the shift of further-out suburbs and exurbs by looking more closely at crucial swing states. In Georgia, for example, 9 out of 10 of the counties that swung the most towards Biden were either an exurb or a middle suburb. The chart below shows how Georgia’s suburban counties voted relative to their densities. Forsyth County is a prime example of the kind of exurb that shifted blue. A fast-growing area on the northern edge of the Atlanta metro, more or less equidistant to downtown and the more rural communities of the Blue Ridge Mountains, the county is solidly red. But Republicans’ margin of victory narrowed by 14 percentage points between 2016 and 2020. These margins are crucial to Republicans, Chinni explains in his election analysis: “Republican candidates need big margins out of those exurb counties to help offset the Democrats big wins in the urban suburbs and big cities.”

In these Atlanta suburbs as elsewhere, it’s density that still forms the main dividing line in American politics. Back in 2012, Dave Troy pegged the inflection point at which places turn from red to blue at 800 people or more per square mile. Our own analysis of 2020 puts it at about 700 people per square mile.

The charts below show the relationship between density and voting between the 2008 presidential election and 2020. The upward slope of the blue line illustrates how the vote becomes more Democratic as places become denser, while the downward slope of the red line shows the opposite: less dense places skew more Republican. Over the past several election cycles, both lines become steeper, showing a growing density divide.

The next chart below highlights the key role that density plays in the suburbs. The denser the suburbs, the more Democratic they voted in 2020. Most of the red counties have densities of fewer than 500 people per square mile. Most of the purple counties are clustered at densities of between 400 and 1,500 people per square mile. And the blue counties are those above 1,500 people per square mile. While there are notable exceptions to this pattern, the basic trend suggests the dominant role suburban density plays in American political life.

American politics is shaped by a new fault line, one that transcends the convenient categories, and stereotypes, of urban and rural areas. Our key elections are increasingly decided in the kinds of places most Americans live, the suburbs.

How Suburbs Swung the 2020 Election

The urban-rural divide is becoming the urban-suburban divide.

A Suburban-Rural Divide Grows

The Suburbs’ Democratic Shift

The Political Shifts of Communities in 2020

In the Atlanta Suburbs, Exurbs Showed Marked Democratic Gains

The Density Effect

Density Divides the Suburbs