Iowa's fastest-growing county flips blue after GOP dominance
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Dallas County, the Midwest's fastest-growing county, swung left in the midterms, breaking a decades-long Republican voting streak in gubernatorial and congressional elections since 2008.
Why it matters: The booming Des Moines metro county is adding thousands of voters annually to its suburbs, making its changing political makeup increasingly important to candidates.
By the numbers: Dallas County backed President Trump in 2024 but gave Democrat Rob Sand 59% of the vote last Tuesday.
- Before this election, Dallas County last backed a Democrat in a gubernatorial race in 2002, with Tom Vilsack, and in a federal race in 2008, with U.S. Sen. Tom Harkin.
- It also supported Democrat Sarah Trone Garriott and gave Democrats a 4-1 majority on the county Board of Supervisors, after recently adding two seats.
The big picture: President Trump's rhetoric and policies on immigration, tariffs and the war in Iran may have alienated some of the county's college-educated suburban voters, says Donna Hoffman, a political science professor at the University of Northern Iowa.
- The county's growth has brought in younger educated professionals, including some who may have traditionally favored Republicans on economic issues.
- Nationally, the once reliably conservative group of voters has swung in more recent history, especially as more women push back against Trump's rhetoric and emphasize other issues like education and health care.
Zoom in: Dallas County's population grew nearly 20% between 2020 and 2025, adding about 18,000 residents.
- More than half of adults have a bachelor's degree, compared with about one-third statewide.
- Median household income exceeds $100,000, compared with roughly $75,000 statewide and $83,000 in neighboring Polk County.
What they're saying: Dallas County Democratic chair Daniel Tallon says the constant influx of residents from Polk County and elsewhere in the state makes the county's changing electorate difficult to pin down.
- The county encompasses rapidly growing suburbs like Waukee and West Des Moines, along with smaller communities like Perry, Adel and surrounding townships.
- Many residents work in Des Moines, and he says they're regularly reminded of rising gas prices as they're driving 20 to 40 minutes each way.
Yes, but: The leftward shift wasn't uniform across the county.
- Democrats made their largest gains in cities, particularly Perry and West Des Moines, while rural areas remained Republican, the Register reports.
- But those gains were large enough to flip the county.
The bottom line: As Dallas County grows its voter base, expect to see more politicians, including presidential candidates, try to crack its electorate.