Iowa County, Iowa

Iowa County is a county in Iowa, United States, home to the Amana Colonies National Historic Landmark along the Iowa River. It had a population of 16,662 at the 2020 census and covers 587 square miles (1,521 km2) centred near 41°41′N 92°04′W.

Marengo is the county seat, and its postal code is 52301. The county has 7 incorporated cities, 8 census-designated places (the eight Amana Colonies villages), and several unincorporated communities, spread across 13 civil townships. Iowa County sits in the Central time zone.

Towns & Villages in Iowa County

Twenty-one named places appear on maps of Iowa County: seven incorporated cities, eight CDPs (the historic Amana Colonies), and six unincorporated crossroads or rural communities. CDP = Census-Designated Place (unincorporated but tracked separately by the Census Bureau); Unincorp. = an unincorporated community with no separate census count.

The eight Amana CDPs sit close together along the Iowa River in the county’s north-central townships and are collectively known as the Amana Colonies — a former communal religious settlement founded in 1855, now a working village cluster and National Historic Landmark. They are separate census places even though several sit less than two miles apart.

Townships

Iowa County is divided into 13 civil townships: English, Greene, Hartford, Hilton, Iowa, Lenox, Lincoln, Marengo, Pilot, Sumner, Troy, Washington and York. The Census Bureau does not publish separate population counts for Iowa’s minor civil divisions, so per-township figures are not available; the table below lists the county seat within each of the three townships where a seat city is confirmed.

ZIP Codes

• 52301 — Marengo (county seat, also serves nearby rural addresses)
• 52361 — Williamsburg
• 52316 — North English
• 52203 — Amana

Several smaller cities and all six unincorporated communities share a ZIP with a neighbouring post office town rather than having their own; those codes are not confirmed here and are omitted rather than guessed.

Geography

Iowa County lies in east-central Iowa on the till plains of the Iowan Surface landform region, drained by the Iowa River, which crosses the county from northwest to southeast, and by the north fork of the English River in the south. The terrain is gently rolling farmland with wooded river bottoms along the Iowa River corridor near the Amana Colonies. Of the county’s 587 square miles, about 586 square miles is land and roughly 1 square mile is water.

Iowa County borders Benton County to the north, Linn County to the northeast, Johnson County to the east, Washington County to the southeast, Keokuk County to the south, Poweshiek County to the west, and Tama County to the northwest.

Demographics

Iowa County’s population was 16,662 at the 2020 census. Williamsburg is the largest city with 3,346 residents, followed by the county seat, Marengo, with 2,435. Middle Amana is the largest of the eight Amana CDPs at 543. With a state figure of a median household income around the Iowa median of $71,433, the county’s largely small-town, agricultural economy runs somewhat below the statewide average in per-capita terms, though Williamsburg’s manufacturing base narrows the gap locally. Density works out to roughly 28 people per square mile.

Economy & Local Life

Row-crop and livestock farming anchors the county’s rural townships, while Williamsburg has grown into the county’s manufacturing and retail hub, helped by its position on Interstate 80 and a large factory-outlet shopping center that draws visitors well beyond the county line. Marengo functions as the government and services center around the county courthouse. The Amana Colonies, centered on Amana, Middle Amana and South Amana, support a tourism and craft economy built on the villages’ communal-era woolen mill, furniture shops, wineries and restaurants, and draw travelers from across eastern Iowa. The Iowa County Fair, held each July in Marengo, is the county’s largest annual gathering.

History

Iowa County was established on February 17, 1843, and organized in 1845, taking its name from the Iowa River, which runs through it. It is one of only a handful of U.S. counties sharing its name with the state that contains it. The county’s best-known chapter began in 1855, when German Pietist settlers known as the Community of True Inspiration relocated from Ebenezer, New York, and founded the seven original Amana villages as a communal religious society; the colonies reorganized as a joint-stock corporation in 1932 in what became known as the Great Change, ending communal living while preserving the villages, which were designated a National Historic Landmark in 1965.

Getting There

Interstate 80 crosses the county east-west through the Amana area and Williamsburg, with U.S. Routes 6 and 151 and Iowa Highways 21, 149, 212 and 220 providing secondary access.

• Iowa City — about 20 miles east
• Cedar Rapids — about 25 miles northeast
• Des Moines — about 90 miles west
• Marengo to Williamsburg — about 8 miles southeast

The nearest commercial airport is the Eastern Iowa Airport (CID) in Cedar Rapids.

Frequently Asked Questions

Where is Iowa County, Iowa?
It is in east-central Iowa, bordering Johnson and Linn counties, home to the Amana Colonies along the Iowa River.

What is the population of Iowa County?
16,662 people at the 2020 census.

How big is Iowa County?
587 square miles (1,521 km2), of which about 586 square miles is land.

What is the county seat of Iowa County?
Marengo is the county seat.

How many towns are in Iowa County?
Seven incorporated cities, eight Amana Colonies CDPs, and several unincorporated communities.

What ZIP codes are in Iowa County?
Confirmed codes include 52301 (Marengo), 52361 (Williamsburg), 52316 (North English) and 52203 (Amana).

Why does Iowa County share its name with Iowa itself?
Both take their name from the Iowa River; the county was organized in 1843, before Iowa achieved statehood in 1846.

More counties in this state: Towns and villages in Iowa.