1st most populous of 99
With 516,185 residents in 2024, Polk County ranks 1st by population among Iowa's 99 counties and is home to 15.9% of the state's residents.

Polk County has the largest economy in Iowa ($63.8 billion GDP) and the 4th lowest homeownership rate (67.4%).
Polk County is home to 516,185 people (2024 estimate) on 572 square miles of land. This page brings together official U.S. Census Bureau population estimates since 2000, the components of change—births, deaths and migration—American Community Survey indicators on income, housing, poverty and education, BEA economic accounts and BLS unemployment.
Pick an indicator to see its long-run evolution.
U.S. Census Bureau: intercensal estimates 2000–2009, Vintage 2020 (2010–2019) and Vintage 2024 (2020–2024), July 1.
| Indicator | Value | Year and source |
|---|---|---|
| Population estimate | 516,185 | 2024 · U.S. Census Bureau |
| Population, 2010 Census | 430,640 | 2010 · U.S. Census Bureau |
| Population, 2000 | 375,627 | July 1, 2000 · Census intercensal |
| Change since 2000 | +37.4% | 2000–2024 · Census |
| International migration | +4,984 | 2024 · Census Vintage 2024 |
| Domestic migration | +1,216 | 2024 · Census Vintage 2024 |
| Birth rate | 12.5 per 1,000 | 2024 · calculated |
| Death rate | 7.7 per 1,000 | 2024 · calculated |
| Population rank in Iowa | 1st of 99 | 2024 · calculated |
| Per capita personal income | $69,800 | BEA, 2024 · official |
| Gross domestic product | $63.8 billion | BEA, current dollars, 2024 · official |
| Median household income | $83,576 | ACS 2020–2024 5-year · official |
| Poverty rate | 10.3% | ACS 2020–2024 5-year · official |
| Bachelor’s degree or higher | 40.3% | Age 25+, ACS 2020–2024 5-year · official |
| Foreign-born residents | 10.1% | ACS 2020–2024 5-year · official |
| Median home value | $262,100 | ACS 2020–2024 5-year · official |
| Median gross rent | $1,149/month | ACS 2020–2024 5-year · official |
| Median age | 36.2 years | ACS 2020–2024 5-year · official |
| Households | 205,358 | ACS 2020–2024 5-year · official |
| Owner-occupied homes | 67.4% | ACS 2020–2024 5-year · official |
Comparable indicators for Polk County, Iowa and the United States.
| Indicator | County | Iowa | U.S. | Reference |
|---|---|---|---|---|
| Population change 2020–2024 | +4.8% | +1.6% | +2.6% | Census Vintage 2024 |
| Birth rate (per 1,000) | 12.5 | 11.2 | 10.6 | 2024 |
| Death rate (per 1,000) | 7.7 | 10.0 | 9.1 | 2024 |
| Net migration rate (per 1,000) | 12.0 | 5.9 | 8.2 | 2024 |
| Population density (/mi²) | 901.8 | 58.0 | 96.3 | 2024 |
| Per capita personal income | $69,800 | $65,225 | $73,204 | BEA, 2024 |
| Median household income | $83,576 | $75,059 | $80,734 | ACS 2020–2024 5-year |
| Poverty rate | 10.3% | 11.1% | 12.5% | ACS 2020–2024 5-year |
| Bachelor’s degree or higher | 40.3% | 31.4% | 35.7% | Age 25+, ACS 2020–2024 5-year |
| Foreign-born residents | 10.1% | 5.9% | 14.1% | ACS 2020–2024 5-year |
| Median home value | $262,100 | $208,000 | $332,700 | ACS 2020–2024 5-year |
| Median gross rent | $1,149/month | $972/month | $1,413/month | ACS 2020–2024 5-year |
| Median age | 36.2 years | 38.6 years | 38.9 years | ACS 2020–2024 5-year |
| Owner-occupied homes | 67.4% | 71.7% | 65.2% | ACS 2020–2024 5-year |
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With 516,185 residents in 2024, Polk County ranks 1st by population among Iowa's 99 counties and is home to 15.9% of the state's residents.
Its population went from 375,627 in 2000 to 516,185 in 2024, a change of +37.4%, compared with +10.7% for Iowa as a whole.
In the year to July 2024 the county recorded 6,453 births and 3,991 deaths, so births outnumbered deaths by 2,462.
Annual Census estimates since 2000 put the county's highest population in 2024, at 516,185.
Polk County has about 901.8 residents per square mile of land, ranking 1st of 99 counties; Iowa averages 58.0.
With a median household income of $83,576 (ACS 2020–2024 5-year), the county ranks 9th of 99 Iowa counties; the state median is $75,059.
Its economy produced $63.8 billion of GDP in 2024 (BEA), 1st largest among 99 Iowa counties.
Real GDP grew 3.2% in 2024, adjusted for inflation (BEA, chained 2017 dollars).