Counties that voted for the Republican or Democratic presidential candidate by 20 percentage points or more

In 1992, 38% of voters lived in landslide counties. 1992 1996 2000 2004 2008 2012 In 2012, 50% of voters lived in landslide counties.

As of 2012, the divide was pretty wide. Half of all voters were living in a county that President Obama or Mitt Romney, the Republican nominee that year, won in a landslide, which is defined here as a county won by 20 percentage points or more.

The proportion of voters living in landslide counties has steadily increased since 1992, a trend that reflects the growing tendency of like-minded people to live near one another, according to Bill Bishop, a co-author of “The Big Sort,” a 2008 book that identified this phenomenon.

Americans have been self-segregating by lifestyle, though not necessarily politics, for several decades, Mr. Bishop said, but lifestyle has grown to reflect politics. “We’re sorting by the way we live, think and — it turns out — every four years or every two years, how we vote.”

Some political scientists expect the landslide trend to continue in the 2016 presidential election. “If anything, I think we’ll see it intensify because Trump has been doing very well among the kinds of voters who tend to live in rural and small-town America,” said Alan Abramowitz, a political science professor at Emory University in Atlanta.

Who Lives in These Counties

Republican landslide counties are generally whiter than Democratic ones.

Each colored stripe represents one landslide county in the nation. This chart shows the percentage of each county that is white.

But whites in Democratic strongholds tend to be wealthier ...

Percentage of white households in each landslide county making more than $100,000 a year.

… and more educated.

Percentage of whites with at least a bachelor’s degree.

People in Republican strongholds are more likely to be married ...

Percentage of the population of each landslide county that is married.

... and religious.

Percentage that adheres to a religion.

People in the bluest counties are more likely to work in “new economy” sectors like technology and health care services.

Percentage of civilian workers in each landslide county employed in the new economy.

A larger share of those in Republican landslide counties rely on “old economy” industries like manufacturing, agriculture and trade.

Percentage of civilian workers in each landslide county employed in the old economy.

How the Counties Compare

There are six times as many Republican landslide counties as Democratic ones.

281 Number of Democratic landslide counties 1,724 Number of Republican landslide counties

Those Republican landslide counties occupy nearly half of the United States.

Land area of Democratic landslide counties Land area of Republican landslide counties

7% of the U.S. 47% of the U.S.

256,061 square miles 1,677,465 square miles

But more people live in the Democratic landslide counties.

Population of Democratic landslide counties Population of Republican landslide counties

90 million people 70 million people

And those counties made up a greater share of the vote in 2012.

Democratic landslide counties Republican landslide counties

28% of all votes 22% of all votes

From 1992 to 2012, the number of Republican landslide counties nearly tripled, while those of Democrats declined.

Number of Democratic landslide counties Number of Republican landslide counties

533 1992 592 1992

281 2012 1,724 2012

Both expanded their share of the vote, but the reddest counties increased more.

Vote share of Democratic landslide counties Vote share of Republican landslide counties

27% 1992 10% 1992