Dallas County area

Population and density of Dallas County

The Census Bureau estimates that 118,457 people lived in Dallas County on July 1, 2025. That ranks #550 of 3,222 county equivalents nationally and #6 of 99 in Iowa. Since the April 1, 2020 estimates base of 99,721, the population has grown by 18,736 (+18.8%), compared with +1.5% for Iowa as a whole.

With 588.2 square miles of land, that is 201 people per square mile (78 per km²), placing Dallas County #638 nationally for density and #6 in Iowa. The median county equivalent has 47 people per square mile; the Iowa median is 26. Put another way, there are about 3.2 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Dallas County

18 incorporated places lie at least partly in Dallas County. Together they are home to 107,075 people (90.4%); the other 11,382 (9.6%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Waukee city, with 34,890 residents in the county. The county seat, Adel city, has 7,098 residents. By land, West Des Moines city is the largest at 47.7 mi² across all its counties. Among places with at least 1,000 residents in 2020, Waukee city grew fastest since then (+45.7%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Dallas County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Dallas County is a central county of the Des Moines-West Des Moines, IA Metropolitan Statistical Area. Its 6 county equivalents have 758,539 residents on 3,612.7 square miles of land; Dallas County accounts for 16.3% of the land and 15.6% of the residents. By combined land it ranks #80 of 393 metropolitan areas, and #83 by population. It belongs to the Des Moines-West Des Moines-Ames, IA Combined Statistical Area.

ZIP codes

25 ZIP Code Tabulation Areas have land in Dallas County; 13 of them have most of their land inside the county, and the others mainly cover neighboring areas.

50003500385003950061500635006650069500705007250109501115012850146501565016750220502335023550261502635026650276502775032350325

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Dallas County

Dallas County shares a land border with 5 county equivalents. It has more land than 4 of them. The largest neighbor is Guthrie County (590.6 mi²) and the smallest is Madison County (561 mi²). Together with its neighbors, Dallas County forms a block of 3,452.6 mi² of land, of which it holds 17%.

How big is Dallas County compared with U.S. states?

Dallas County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.8 times as much. Iowa’s county land could hold about 95 areas the size of Dallas County.

Another way to picture it: the same land area would fill a square about 24.3 miles (39 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Dallas County?

Dallas County has more land than 1,556 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Dallas County at #1,773 nationally by total area, 107 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 0.6%, compared with a national county-equivalent median of 1.2% — 0.6 percentage points lower. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Dallas County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.