Between 250,000 and 300,000 Iowans will head to community centers, church basements and school auditoriums on Monday to begin the months-long process of choosing Democratic and Republican presidential nominees.
When the results roll in, they will reflect the choices of a state deeply divided along economic, cultural and political lines. Those divisions will help explain who wins each party’s caucuses, and why.
Here are eleven maps that help make sense of Iowa and its electorate:
Population by County, 2010
Few divisions are more deeply felt in Iowa than the urban-rural schism. Most Iowa voters are concentrated in a few densely populated counties such as Polk, home of Des Moines, Johnson and Linn, homes of Cedar Rapids and Iowa City, and Pottawattamie, home of Council Bluffs.
Forty-six of Iowa’s 99 counties have fewer than 15,000 residents. Those more rural areas are far more conservative than the more populous city centers. They’re also losing population, while the urban centers grow.
Population Change by County, 2000 to 2010
There’s a big difference, too, between urban and rural counties in the area of educational attainment. More than 40 percent of residents in Dallas, Johnson and Story counties have college degrees, according to U.S. Census Bureau data; fewer than one in five residents of more rural counties have the same educational reach.
Bachelor’s Degrees by County
Western rural counties such as Pocahontas, Sac, Calhoun, Audobon and Adams are bleeding population at the fastest clips. Those five counties each lost more than 10 percent of their populations between the 2000 and 2010 Censuses. At the same time, Dallas County, where suburbs of Des Moines are growing quickly, grew by 62 percent. Polk, Story (Ames), Warren and Madison counties all grew by more than 10 percent; so did counties around Cedar Rapids and Iowa City.
2012 Republican Presidential Caucus Results
The urban-rural divide shows up in political geography, too. In 2012, former Massachusetts Gov. Mitt Romney virtually tied with former Sen. Rick Santorum (R-Pa.), despite the fact that Santorum won many more counties. Romney won heavily populated counties around Des Moines, Iowa City and Cedar Rapids, while Santorum ran up the score in lesser-populated rural areas.
The orange counties on the east side of the state: Those are counties former Rep. Ron Paul (R-Texas) won. Paul attracted libertarian-leaning voters — the same voters who propelled Rep. Rod Blum (R) to Congress in the northeastern corner of the state, one of the most significant surprise upsets in the 2014 midterm elections.
Romney won just one of those 46 counties with fewer than 15,000 residents — Fremont County, in the southwest corner of the state. Santorum won 36, Paul took seven and former Texas Gov. Rick Perry won two.
2014 Republican Senatorial Primary Results
Don’t buy the narrative that Ernst was a creation of the tea party movement; by the time she rolled over her Republican opponents, she had become a favorite of the party establishment. It was an open secret that Ernst had been nudged into the race by Republican Gov. Terry Branstad.
Branstad’s own re-election bid serves as a better geographic outline of the conservative-establishment schism within the Iowa Republican Party. In 2010, when Branstad returned to the governor’s office after twelve years away, he had to get through another pillar of Iowa’s religious right, Bob Vander Plaats.
Vander Plaats won 24 of Iowa’s 99 counties, and he held Branstad under 50 percent in another 18. And while conservatives reliably win northeastern counties and rural southern counties, take note: Branstad scored less than 50 percent in Polk, and Vander Plaats won Story County outright. There are plenty of conservatives in the Des Moines area for a candidate such as Sen. Ted Cruz (R-Texas) to pick off.
2010 Republican Gubernatorial Primary
Religious voters play a big role in the Republican caucuses; every four years, the political media hones in on home-schoolers rallying around one candidate or another. Zoom in on the northwestern counties, where their influence becomes clear. Those seven counties were the only significant area then-state Sen. Joni Ernst lost in her run for a U.S. Senate seat in the 2014 Republican primary. They went for Sam Clovis, a conservative radio host with deep ties to the Christian right.
Those northwestern counties have a higher percentage of evangelicals and members of the Reformed Church of America than other parts of the state.
Iowa is mostly Protestant; a little under two-thirds of the state self-identifies as some kind of Protestant denomination. About one in five Iowans are Catholic, with significant populations along both the Missouri and Mississippi rivers. Methodists, Lutherans and Evangelical Lutherans make up the plurality of religious observers in pockets around the state, according to data compiled by the Association of Statisticians of American Religious Bodies.
Largest Religion by County
In 2008, Romney won counties along both rivers that border Iowa on the east and west. He lost the heavily evangelical northwestern counties to former Arkansas Gov. Mike Huckabee, who beat Romney by a wider margin than Santorum did four years later. The big difference: Huckabee took Polk County (again, proof that conservatives have a presence in Des Moines), which Romney would win in 2012.
The counties along the Missouri River, on Iowa’s western border, are called the Loess Hills, a geological formation created by glaciers moving through the Missouri River Valley during the last ice age.
2008 Republican Caucus Results
On the Democratic side, the last significant caucus battle illustrated its own geographic divide. Hillary Clinton won most of the Loess Hills, and a dozen rural counties on the northern part of the state. Then-Sen. John Edwards of North Carolina was strongest in southern rural counties, though he had his own bastions of support up north.
Then-Sen. Barack Obama won by running up the score in the more heavily populated urban cores; Obama won Polk and Linn counties by double digits, and he won Johnson and ccott Counties, in the eastern slice of the state, by more than 20 points each.
2008 Democratic Caucus Results
Iowa suffered less through the recession than the rest of the nation. At the depths of the recession, in August 2009, the unemployment rate hit 6.6 percent — almost three and a half points lower than the national rate in 2010.
But that doesn’t mean all of Iowa was immune. The eastern side of the state, which includes manufacturing hubs around the Quad Cities and south down the Mississippi River, suffered huge job losses as plants closed and the economy dried up.
Unemployment Rate by County
Even today, southeastern Iowa is struggling to recover. Tiny Lee County sports the highest unemployment rate in the state at 6.3 percent. Des Moines County (not the same as Polk County’s largest city), Scott, Clinton and Jackson counties all have unemployment rates above the national average.
In those evangelical counties in the northwest, there are hardly any unemployed people left: Lyon County, exactly opposite from Lee, has an unemployment rate of just 2.6 percent.
Unemployment Rate by County
Low unemployment rates lead to higher wages, another area where the urban-rural divide is evident. In high-unemployment rural counties, the median income in Iowa hovers around $40,000 per household. Lower-unemployment rural counties, like Lyon, have higher median incomes.
But again, urban cores generate a better income for their residents. The median income around Des Moines, Cedar Rapids and the suburbs of Omaha have median incomes almost 50 percent higher than their rural counterparts.
Median Income by County
The race for delegates to the Democratic and Republican national conventions this year will be fought along similar lines. Expect Cruz, popular with evangelical voters and determined to make his presence felt in rural counties, to win many of the same areas Huckabee and Santorum took in 2008 and 2012. Real estate tycoon Donald Trump is likely to do well in college counties — Story, Polk, Johnson and Linn — and perhaps in more blue-collar working areas in the southeast corner of the state.
The Democratic map is likely to look much different than the 2008 race. Recent surveys show Sen. Bernie Sanders (I-Vt.) running just about even with Clinton, though his support comes more from college counties. Clinton will bank on winning those more rural counties that went for Edwards in 2008, in hopes that’s enough to build on her success last time around in the Loess Hills.