🇺🇸 United States ZIP Code

STANDARD

51040

Onawa

ZIP Code 51040 is a standard zip code serving Onawa, Onawa, Iowa (IA), in Monona County, United States. It has an estimated population of 3,712 with a median household income of $38,969. The area falls within the America/Chicago timezone.

Median Household Income vs. National Average

Location

Country: 🇺🇸 United States
State / Province: Iowa (IA)
County: Monona
City: Onawa
Timezone: America/Chicago

Coordinates

Latitude: 42.037000
Longitude: -96.107200

Geographic Details

Land Area: 152.22 mi²
Water Area: 2.14 mi²
Population Density: 24.0 people per mi² (25th percentile)
Bounding Box: 42.126830°N, 41.945606°S, -95.903261°E, -96.279536°W

With 3,712 residents spread across 152.22 square miles, this area has a population density of 24.0 people per square mile.

Demographics

3,712

Population

50th percentile

$38,969

Median Income

25th percentile

$81,700

Median Home Value

20th percentile

152.22 mi²

Land Area

The median household income in 51040 is $38,969, and the median home value is $81,700. This is below the national average for household income.

Housing

1,906

Total Units

1,644

Occupied Units

86.3%

Occupancy Rate

Similar ZIP Codes in Iowa

ZIP codes with similar median household income in Iowa.

52342

Toledo

$42,059

52554

Eldon

$35,568

50447

Kanawha

$38,636

52155

Lime Springs

$43,864

50014

Ames

$37,661

51640

Hamburg

$37,500

50316

Des Moines

$37,424

52142

Fayette

$42,098

Frequently Asked Questions

What information is available for each ZIP code?

Each ZIP code page shows city, state, county, geographic coordinates, timezone, population, median household income, median home value, housing units, land area, population density, commute time, educational attainment, area codes, and ZIP code type (Standard, PO Box, or Unique).

What are the different types of ZIP codes?

There are three types of ZIP codes: Standard (residential and commercial delivery areas), PO Box (assigned to post office box sections), and Unique (assigned to a single high-volume address like a government agency or large company). Standard ZIP codes are the most common.

How often is ZIP code data updated?

ZIP code assignments are updated quarterly by the USPS. Demographic data comes from the US Census Bureau's American Community Survey (ACS), which releases new 5-year estimates annually. ZipFYI updates its data to reflect the latest available information.

What is population density and why does it matter?

Population density measures the number of people per square mile in a ZIP code area. It helps identify urban vs. rural areas, affects real estate values, impacts service availability, and is used in market analysis. Dense urban ZIP codes may have 50,000+ people per square mile.

How are ZIP code boundaries determined?

ZIP code boundaries are determined by the USPS based on mail delivery routes, not political or geographic boundaries. They follow carrier routes and may cross city, county, or even state lines. Boundaries can change when the USPS reorganizes delivery operations.

What does median household income tell me about a ZIP code?

Median household income is the middle value when all household incomes in a ZIP code are sorted. Half of households earn more and half earn less. It is a better indicator of typical earnings than average income, which can be skewed by very high or very low outliers.