Overview
Polk County is Iowa's most populous county, home to 497,441 residents (Census ACS 5-Year, 2023) and the state capital, Des Moines. That population figure places it above 95% of all U.S. counties and at the 99th rank among Iowa's 99 counties. It's the economic and political center of the state by nearly every measure: largest labor force, highest total income, most bank branches, most housing units.
The median household income sits at $81,621 (Census ACS 5-Year, 2023), higher than 86% of U.S. counties. The median age is 36.2 years (Census ACS 5-Year, 2023), younger than 88% of counties nationally. That combination of relative youth and above-average income shapes much of what follows.
Demographics
Polk County skews young. At 36.2 years, the median age falls below that of 88% of U.S. counties and 94% of Iowa counties (Census ACS 5-Year, 2023). A large working-age population drives the labor force numbers discussed later.
Educational attainment runs high. 39.5% of adults hold a bachelor's degree or higher (Census ACS 5-Year, 2023), placing the county above 91% of counties nationally and 95% within Iowa. That's a meaningful gap over the national average of roughly 33%.
The racial composition is 74.1% white, 7.4% Black, 4.9% Asian, and 0.1% Native American, with 10% identifying as Hispanic or Latino (Census ACS 5-Year, 2023). Compared to the rest of Iowa, Polk County is notably more diverse. Its Black population ranks higher than 97% of Iowa counties, and its Asian population exceeds 96% of counties in the state. The Hispanic share surpasses 86% of Iowa counties.
Education
Total enrollment across Polk County schools reached 79,009 students (Education Data Portal, 2021), the highest in the state. Per-pupil spending was $15,270 (Education Data Portal, 2020), just above the national average of roughly $15,000. The student-teacher ratio of 15.4:1 (Education Data Portal, 2021) is close to the national benchmark of 15.5:1.
The graduation rate is where Polk County falls short. At 83.5% (Education Data Portal, 2019), it trails the national average of about 87% and ranks lower than 72% of U.S. counties. Within Iowa, it sits at the 6th rank out of 99, meaning 93 counties in the state post higher graduation rates. For a county with this level of income and educational attainment among adults, that gap is worth watching. The data is from 2019, so more recent figures may tell a different story, but it's the most current available through this source.
Economy & Employment
The labor force in Polk County totals 289,649 people, with 279,540 employed (BLS LAUS, 2025). The unemployment rate is 3.5% (BLS LAUS, 2025), lower than 61% of U.S. counties and roughly in line with the broader Iowa economy.
Household income tells a strong story. Median household income of $81,621 and per capita income of $44,008 (Census ACS 5-Year, 2023) both rank higher than 86% and 88% of U.S. counties, respectively. IRS data shows an average adjusted gross income of $85,608 per return (IRS Statistics of Income, 2021) across 242,580 total returns, with total AGI of $20.8 billion.
The poverty rate is 9.9% (Census ACS 5-Year, 2023). That's lower than 74% of U.S. counties, though it sits near the middle of the pack within Iowa, at the 47th state rank. For a county with high median income, a poverty rate near 10% points to income distribution gaps common in metro areas with both professional-class jobs and lower-wage service work.
Housing & Cost of Living
Median home value is $248,400 (Census ACS 5-Year, 2023), higher than 75% of U.S. counties and 95% of Iowa counties. That state ranking reflects how much Des Moines metro housing costs exceed the rest of Iowa.
Median gross rent is $1,113 per month (Census ACS 5-Year, 2023), above 81% of U.S. counties and 98% of Iowa counties. Bedroom-specific fair market rent breakdowns from HUD are not available for Polk County (HUD Fair Market Rents, 2026).
The total housing stock includes 215,016 units, with 12,612 vacant (Census ACS 5-Year, 2023). The vacancy rate of 5.9% is lower than 92% of U.S. counties and 94% of Iowa counties. A tight housing market like this, paired with the county's relatively high rents, suggests limited slack for new residents or lower-income renters.
At median income levels, a household earning $81,621 could reasonably afford rent of about $2,040 per month under the standard 30% threshold. Median rent at $1,113 leaves room, but that median figure masks the range. The combination of low vacancy, high demand from a large labor force, and limited supply could push rents upward.
Health & Wellness
Polk County's health data shows results generally better than the national midpoint across most indicators. Obesity stands at 36.9% (CDC PLACES, 2023), higher than 38% of U.S. counties. High blood pressure affects 30.1% of adults, lower than 76% of U.S. counties (CDC PLACES, 2023). Diabetes prevalence is 9.6%, lower than 75% of counties nationally (CDC PLACES, 2023).
Depression affects 21.7% of adults (CDC PLACES, 2023). Poor mental health days (17.4%) and poor physical health days (12.2%) both rank better than roughly three-quarters of counties nationally (CDC PLACES, 2023).
Cholesterol screening stands at 83.1%, and 74.8% of adults had an annual checkup (CDC PLACES, 2023). Those preventive care numbers sit near the national middle.
The uninsured rate is 7.6% (CDC PLACES, 2023), lower than 89% of U.S. counties. That's a meaningful marker of healthcare access in a metro area with multiple hospital systems and a large employer base.
Climate & Natural Disasters
Polk County averages 52.1°F annually (NOAA Climate Data Online, 2025), with highs around 62.1°F and lows around 42.1°F. That's cooler than 59% of counties nationally. Winters carry real weight: 30.4 inches of snow per year (NOAA Climate Data Online, 2025), more than nearly three-quarters of the country.
Annual precipitation is 36.2 inches (NOAA Climate Data Online, 2025), close to the national midpoint. But rainfall timing matters more than volume here.
Flooding is Polk County's defining hazard. Eight of the county's 20 federal disaster declarations since 1965 have been flood events (FEMA OpenFEMA, 2026). The pattern runs across decades, from the spring floods of 1969 through the major 1993 event to a 2019 declaration. That's not bad luck. It's topography and a river system that responds fast to heavy spring rains.
Severe storms are the other consistent threat. Five separate storm declarations since 2004, including two in the spring of 2024 alone (FEMA OpenFEMA, 2026). A tornado declaration in May 2024 confirms the county sits firmly in the zone where Great Plains weather systems stall and spin up.
Twenty total declarations puts Polk County near the national median for disaster frequency, above 46% of U.S. counties (FEMA OpenFEMA, 2026). Given its size and the density of people in Des Moines, that's a number worth taking seriously. Flood insurance isn't optional for anyone near the Des Moines or Raccoon rivers.
Financial Profile
IRS data from 2021 shows 242,580 tax returns filed in Polk County, with total income of $20.9 billion and total adjusted gross income of $20.8 billion (IRS Statistics of Income, 2021). Average income per return was $86,326, placing the county above 88% of U.S. counties and 93% within Iowa.
Banking infrastructure is substantial. Polk County has 70 FDIC-insured bank branches holding $17.7 billion in total deposits (FDIC Summary of Deposits, 2023). That branch count ranks above 93% of U.S. counties, and the deposit total exceeds 96%.
Social Security reaches a large share of the population. There are 88,060 OASDI beneficiaries in Polk County (SSA OASDI, 2024), roughly 17.7% of the total population. That figure ranks above 95% of counties nationally in raw count, though the per-capita rate is relatively modest given the county's younger median age.
Key Comparisons
Polk County's clearest advantage over most U.S. counties is economic. Income, employment, and banking access all rank in the top 15% nationally. Educational attainment among adults reinforces that position.
Within Iowa, it's dominant by scale. Population, labor force, housing units, enrollment, bank branches, and total deposits all rank at or near the 99th position in the state. It's the obvious economic hub.
Where Polk County doesn't stand out: graduation rates (lower than 72% of U.S. counties), obesity (higher than 38%), and the poverty rate, which sits near Iowa's median despite the county's high income levels. The gap between average income ($86,326 per IRS) and a 9.9% poverty rate suggests a split between higher earners and those in lower-wage sectors.
Housing vacancy at 5.9% is tighter than 92% of U.S. counties, creating potential pressure on affordability even though current rent levels remain manageable relative to income. The county's young median age (lower than 88% nationally) combined with its strong labor market could sustain demand.
Climate risk remains a factor. Twenty FEMA disaster declarations over six decades, concentrated in floods and severe storms, place the county near the middle nationally but well above areas without recurring natural hazard exposure.
Data Sources
- Census ACS 5-Year, 2023 (population, income, housing, demographics, education attainment, commute, poverty)
- BLS LAUS, 2025 (unemployment, employment, labor force)
- CDC PLACES, 2023 (health metrics, insurance coverage)
- HUD Fair Market Rents, 2026 (bedroom-specific rent data not available)
- FEMA OpenFEMA, 2026 (disaster declarations)
- IRS Statistics of Income, 2021 (tax returns, income)
- FDIC Summary of Deposits, 2023 (bank branches, deposits)
- NOAA Climate Data Online, 2025 (temperature, precipitation, snowfall)
- SSA OASDI, 2024 (Social Security beneficiaries)
- USDA Census of Agriculture, 2022 (no data available for Polk County)
- Education Data Portal, 2019-2021 (enrollment, spending, graduation rate, student-teacher ratio)