The 6 Fastest-Growing Counties in Iowa Are Exploding in Growth

Written by Kyle Glatz
Updated: October 30, 2023
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Iowa is a state in the Midwest that has experienced slow growth in recent years. According to the U.S. Census Bureau, the state had a population of 3,046,355 people in 2010. The population climbed to 3,190,369 in 2020. Moreover, the state has experienced a 0.3% growth from 2020 to 2022. Discover 6 of the fastest-growing counties in Iowa!

For 2022, Polk County in Iowa had the most growth by population in the state.

Interestingly, many of the counties in this state are slowly losing their population. Yet, the ones that are gaining residents on this list are making up for those losses and overcoming them.

6. Madison County

Historic Roseman Covered Bridge in Madison County Iowa

Madison County is in southwestern Iowa.

©Yeokum Photography/

Population GainPercent Gain
Gained 491 Residents2.97%

Madison County had 16,545 residents in 2020. Yet, that number rose to 17,036 people in 2022. The small county experienced a gain of almost 3% of its population, 491 additional people. While that is a small gain, it is a significant addition in terms of percentage gain.

Based on its population growth, Madison County is one of the fastest-growing counties in the state. Madison County is in southwestern Iowa, southwest of Des Moines. The largest city in the region is Winterset, an area known for being the birthplace of John Wayne.

5. Story County

The Central Campus of Iowa State University in the fall

Story County is home to Iowa State University.

©Harris Dzulkarnain/

Population GainPercent Gain
Gained 1,137 Residents1.15%

The population of Story County from the 2020 Census was 98,536. That number rose to 99,673 people based on the estimates for 2022. That represents a gain of 1,137 people throughout the state, equivalent to a 1.15% change.

Story County is located in central Iowa. The largest city in the county is Ames. This region is home to Iowa State University. The university certainly contributes to the population of the county.  

4. Warren County

Map view of Cedar Rapids and Iowa State

Warren County is south of Des Moines.

©Tudoran Andrei/

Population GainPercent Gain
Gained 1,925 Residents3.67%

The 2020 Census revealed that Warren County was home to 52,402 people. The estimates for July 2022 showed that the county was then home to 54,327 people. Warren County gained 1,925 people over the last two years; that is equivalent to a population increase of 3.67% over two years.

Warren County is another county in southern Iowa, and it is just south of Des Moines. The largest city in this region is Indianola, and it has a population of over 15,000 people.  

3. Johnson County

Upper Iowa River

A part of the Iowa River flows through Johnson County.

©Dustin Bohlken/

Population GainPercent Gain
Gained 3,559 Residents2.3%

Johnson County had 152,861 residents during the 2020 Census. However, the population swelled to 156,420 in 2022. The population in the region increased by 2.3% between 2020 and 2022, a gain of 3,559 people. This is a modest gain in residents and a somewhat significant population increase.

Johnson County is in eastern Iowa. This county is south of Cedar Rapids, and it contains Iowa City. The county is home to a few important waterways. These include a portion of the Iowa River along with Coralville Lake and Lake Macbride.

2. Dallas County

Raccoon River

Raccoon River flows through southern Dallas County.

©Zena E/

Population GainPercent Gain
Gained 8,339 Residents8.37%

Dallas County is one of the fastest-growing counties in Iowa where more people are settling down to live. The original population in the state in 2020 was 99,677 people, but that number grew to 108,016 people. That means 8,339 more people moved to the state, an increase of 8.37%.

Dallas County is just west of Polk County, the county that contains Des Moines. The largest city in the county is Waukee, and it had a population of 24,284 people as of the 2020 Census. However, this number has increased to around 31,000 people based on new estimates.

1. Polk County

Des Moines, Iowa during winter

Des Moines has experienced rapid growth over the last decade.


Population GainPercent Gain
Gained 8,678 Residents1.76%

Polk County, Iowa was home to 492,411 people when the last census was performed. The Census Bureau estimates that the county gained a significant number of residents and that the population in the region was nearly 501,089 people. This is a 1.76% increase in population, but it is also the largest increase in terms of residents in the entire state between 2020 and 2022.

Polk County is the largest county in the state by population, and it has the city of Des Moines within it. Des Moines has a population of 214,133 people, almost half the number of people in the entire county. Moreover, this county has almost a sixth of the population of the entire state.

Polk County is top among the fastest-growing counties in Iowa. Much of this state’s growth stems from the population increases in the Des Moines Metro area. After all, the overall population in the state rose just 0.3% between 2020 and 2022. Many of the counties in the state experienced a slight decrease in population. However, the growth in Polk County and others offset these losses and overcame them.

Des Moines continues to grow because it has a good jobs market, affordability, low crime, and new attractions becoming available all the time. The next census will reveal whether or not this level of growth is sustainable or not.  

Summary of the Fastest-Growing Counties in Iowa

RankCountyPopulation GainPercent Gain
1Polk County+ 8,678 Residents1.76%
2Dallas County+ 8,339 Residents8.37%
3Johnson County+ 3,559 Residents2.3%
4Warren County+ 1,925 Residents3.67%
5Story County+ 1,137 Residents1.15%
6Madison County+ 491 Residents2.97%

The photo featured at the top of this post is © rarrarorro/

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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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