Woodbury County area

Population and density of Woodbury County

The Census Bureau estimates that 106,649 people lived in Woodbury County on July 1, 2025. That ranks #596 of 3,222 county equivalents nationally and #7 of 99 in Iowa. Since the April 1, 2020 estimates base of 105,981, the population has grown by 668 (+0.6%), compared with +1.5% for Iowa as a whole.

With 872.9 square miles of land, that is 122 people per square mile (47 per km²), placing Woodbury County #867 nationally for density and #9 in Iowa. The median county equivalent has 47 people per square mile; the Iowa median is 26. Put another way, there are about 5.2 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 Woodbury County

15 incorporated places lie at least partly in Woodbury County. Together they are home to 98,668 people (92.5%); the other 7,981 (7.5%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Sioux City city, with 86,354 residents in the county (the city extends into 1 other county). Among places with at least 1,000 residents in 2020, Sergeant Bluff city grew fastest since then (+6.2%).

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

Metropolitan area

Woodbury County is a central county of the Sioux City, IA-NE-SD Metropolitan Statistical Area. Its 3 county equivalents have 145,738 residents on 1,599.3 square miles of land; Woodbury County accounts for 54.6% of the land and 73.2% of the residents. By combined land it ranks #206 of 393 metropolitan areas, and #302 by population. It belongs to the Sioux City-Le Mars, IA-NE-SD Combined Statistical Area.

ZIP codes

26 ZIP Code Tabulation Areas have land in Woodbury County; 19 of them have most of their land inside the county, and the others mainly cover neighboring areas.

5100451006510075101551016510185101951026510285103051034510395104451048510525105451055510565110151103511045110551106511085110951111

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 Woodbury County

Woodbury County shares a land border with 7 county equivalents, including 3 in Nebraska and South Dakota. It has more land than every one of them. The largest neighbor is Plymouth County (862.8 mi²) and the smallest is Dakota County (264.4 mi²). Together with its neighbors, Woodbury County forms a block of 4,558.2 mi² of land, of which it holds 19.1%.

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

Woodbury County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.2 times as much. Iowa’s county land could hold about 64 areas the size of Woodbury County.

Another way to picture it: the same land area would fill a square about 29.5 miles (47.5 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 Woodbury County?

Woodbury County has more land than 2,290 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 Woodbury County at #1,032 nationally by total area, 100 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 Woodbury 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.