🇺🇸 United States ZIP Code

STANDARD

51003

Alton

ZIP Code 51003 is a standard zip code serving Alton, Alton, Iowa (IA), in Sioux County, United States. It has an estimated population of 1,700 with a median household income of $60,391. The area falls within the America/Chicago timezone.

Median Household Income vs. National Average

Location

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

Coordinates

Latitude: 42.978200
Longitude: -96.017300

Geographic Details

Land Area: 55.71 mi²
Water Area: 0.03 mi²
Population Density: 31.0 people per mi² (30th percentile)
Bounding Box: 43.062941°N, 42.909772°S, -95.899558°E, -96.078390°W

With 1,700 residents spread across 55.71 square miles, this area has a population density of 31.0 people per square mile.

Demographics

1,700

Population

35th percentile

$60,391

Median Income

70th percentile

$123,200

Median Home Value

45th percentile

55.71 mi²

Land Area

The median household income in 51003 is $60,391, and the median home value is $123,200.

Housing

674

Total Units

646

Occupied Units

95.8%

Occupancy Rate

Similar ZIP Codes in Iowa

ZIP codes with similar median household income in Iowa.

50424

Buffalo Center

$53,679

51024

Hinton

$65,625

52161

Ossian

$56,719

50258

Union

$52,132

52405

Cedar Rapids

$55,406

50660

New Hartford

$64,511

52336

Springville

$60,625

50003

Adel

$65,588

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.