Monona County, Iowa

Monona County, Iowa, has 8,539 residents (July 2025 estimate). Its county seat is Onawa. It uses Central Time and covers 694 sq mi (1,798 km²) of land.

Monona County in Iowa

Monona County and its neighbors (simplified outlines). Open in OpenStreetMap ↗

Resident population, July 2025: 8,539
Land area: 694 sq mi (1,798 km²)
County seat or government: Onawa
Time zone: Central TimeUTC-06:00 in January; UTC-05:00 in July
Median household income: $68,377 ± $6,651
Median home value: $142,900 ± $13,872
Median rent, with utilities: $855 ± $72
Homes lived in by their owners: 75.7% ± 3.3 points
County type: County
Metro or micro area: Outside any metro or micro areaNext to: Sioux City, IA-NE-SD metro area and Omaha, NE-IA metro area
Water area: 4.86 sq mi (12.6 km²)
State: Iowa
County code (FIPS): 19133
Coordinates (central point): 42.049432, -95.956566

Open this point in the location finder

These coordinates mark a central point for the area, not a street address. Income, home value, rent and homes lived in by their owners: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, ± margin at 90% confidence; checked on October 13, 2026.

Time zones in Monona County

Time zone	Local time and UTC offset	Next clock change
Central TimeAmerica/Chicago	UTC-06:00 in January; UTC-05:00 in July. Enable JavaScript for the live clock.	Enable JavaScript for upcoming changes.

Near a time-zone line, check where you are with the time-zone finder. Your phone’s setting can differ.

ZIP Code areas, largest first

510403,500 people
515291,732 people
510341,674 people
510551,346 people
510631,072 people
51026910 people
51060706 people
51558549 people
51019448 people
51010425 people
51523379 people
51572371 people

All 15

51056346 people
51545267 people
5105139 people

15 ZIP Code areas overlap Monona County. People counts are 2020–2024 estimates for each whole ZIP area. Mailing ZIPs can differ; check an address with USPS ZIP Code Lookup.

Official county information

We don’t have a website for this county yet. The US government’s local-office directory ↗ lists its offices. A geographic lookup cannot determine eligibility, tax liability or a court obligation.

Townships in Monona County, largest first

All 19

Belvidere Township202 people
Jordan Township184 people
Grant Township158 people
Center Township119 people
Fairview Township109 people
Willow Township90 people
Sioux Township46 people

People counts are American Community Survey 2020–2024 5-year estimates. All townships in Iowa, by county

School districts in Monona County, largest first

West Monona Community School District4,024 people
Maple Valley-Anthon Oto Community School District3,573 people
Westwood Community School District3,411 people
Boyer Valley Community School District2,509 people
Woodbine Community School District2,470 people
West Harrison Community School District2,464 people
Charter Oak-Ute Community School District1,864 people
Whiting Community School District1,105 people

Districts with land in the county; a district can cross county lines. People counts are American Community Survey 2020–2024 5-year estimates. A district boundary doesn’t decide which school a student attends.

Cities, towns and communities, largest first

These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.

Bordering areas, nearest first

Distances are straight lines between map points.

Before using this answer on a form

Use a precise point for address-level questions. A device accuracy circle can cross a boundary; confirm tax, voting or jury details with the responsible office.

Find the county where you are now, check its ZIP area, or check the time zone where you are.

See this county on Census.gov ↗

Areas that only touch the edge

These areas meet the boundary only along a sliver. Most addresses here are not in them; for an address near the line, check with the county.