Lowest turnout since 2000, or what legacy media calls A Historic Win.

Results released so far estimated that the final turnout will be around 110,000 voters of an estimated 718,901 registered republicans in a state population of 3.21 million.

Republican front-runner Donald Trump added Iowa’s most religious regions to his strongholds in Monday’s caucuses. He combined religious areas with the state’s lower-income and less educated counties to pull a majority of all caucus voters, more than double what he earned eight years ago.

Trump dominated the caucuses in the style of other Republican winners of the past 20 years, a pattern that works in Iowa but did not propel them to win the nomination. Meanwhile, Trump’s weakest performance was in the parts of Iowa that more closely resemble the rest of the country, with fewer White evangelical Christians, fewer farmers and more people living in cities with higher education and more income.

Trump pulled the evangelical Christian voters who pushed Arkansas Gov. Mike Huckabee to victory in the Iowa caucuses in 2008, Sen. Rick Santorum of Pennsylvania in 2012 and Sen. Ted Cruz of Texas in 2016. None of them won the nomination.

With over 50 percent of the caucus vote in Iowa and strong leads in polls in the other early primary states, Trump remains a strong favorite to win the Republican nomination for the third time in a row. His victory, however, included potential weak spots for the general election.

Education

Education proved to be a particularly strong divider between where Trump did best and worst. The gap in support for Trump widened between regions with more or less education. In 2016, he got 29 percent of the vote in the parts of the state with the lowest levels of college education and 22 percent in the counties with the highest levels.

In 2024, that spread more than doubled to 18 percentage points. Trump’s worst result Monday was 34 percent in Story County, home to Iowa State University in Ames. His second worst was 36 percent in Johnson County, home to the University of Iowa in Iowa City.

Evangelicals

Evangelical Christian voters moved to Trump in a way that highly educated voters did not. In 2016, Trump fared poorly in the most evangelical areas, with his share of the vote declining as the share of evangelicals grew. That pattern was reversed this year. He won 58 percent of the vote in the most religious counties compared with 54 percent in the least religious.

Cruz was the favorite of voters in the most evangelical areas eight years ago. The northwest quadrant of the state was Cruz’s strongest and Trump’s weakest. This year, Trump won some of his best results there, matching the much less evangelical region in the northeast. Overall, Trump improved by 35 percentage points in the most evangelical counties, one of his biggest gains. For example, in small Hancock County in the northern tier of the state, which has one of the highest share of evangelical voters, Trump got 19 percent of the vote in 2016. He won 65 percent Monday night.

Income

Trump’s appeal grew especially strongly in the counties with the lowest median household income, where he won 65 percent of the vote. He improved by 36 points in those areas, the largest boost of any demographic group measured. His performance in the wealthiest areas was much less impressive: 45 percent of the vote for a gain of 23 percentage points.

Trump’s biggest share of the vote Monday night was in Keokuk County, where the typical household income was $52,000 in 2020 Census data, among the lowest in the state. He won 75 percent of the vote there compared with 31 percent eight years ago.

Trump won less than 50 percent of the vote in only 12 of the state’s 99 counties. Those are the counties where Trump finished behind both Cruz and Sen. Marco Rubio of Florida in 2016. They are collectively the larger, wealthier, more urban and suburban counties.

Trump’s best gains in evangelical areas may be less predictive of success around the country than the results in Iowa’s bigger metropolitan areas.

Who came second in Iowa?

Florida Gov. Ron DeSantis was the clear runner-up in most counties that strongly preferred Trump. Of the seven counties where Trump won more than 70 percent, DeSantis was the second choice in six of them. These were largely small, rural counties like Wapello and Appanoose in the state’s southeast that voted for Trump in the 2016 primary, as well. However, DeSantis came the closest to winning in larger evangelical counties like Sioux, which Cruz dominated in 2016.

In contrast, former South Carolina governor Nikki Haley performed best in counties where Trump was weakest. Most of her second-place finishes came in counties where Trump received under half of the vote. She came in a close second in Story County, where she received 30 percent of the vote to Trump’s 34 percent.

About this story

Data from the U.S. Census and state election results via the Associated Press. The evangelical share is from the the Association of Religion Data Archives 2020 county census of religion.