51003 ZIP Code — Alton, IA
Sioux County, Iowa
ZIP code 51003 is located in Alton, Iowa, within Sioux County. It covers approximately 54.36 square miles and serves a population of 1,761 residents. This is a standard ZIP code in the Central (CT) timezone, served by area code 712.
About ZIP code 51003
The housing stock consists of predominantly single-family detached homes. Most homes were built in the pre-1940, giving the area an established character. Median home value is $215,800. Owner-occupancy is high at 88%, well above the national average.
Median household income is $85,536.
The dominant occupation class is management, business, and professional, with education and healthcare as the leading industry. The average commute of 13 minutes is near the national average.
Educational attainment is near the national average, with 24% of residents holding a bachelor's degree or higher.
1,761
population
54.36
sq mi land
Standard
ZIP type
Central (CT)
timezone
51003 ZIP code map
Cities in ZIP code 51003
Below are the cities the US Postal Service accepts for ZIP code 51003. Using any city not on this list may result in mail delivery delays.
| City | Status |
|---|---|
| Alton | Acceptable |
| Alton | Preferred |
Nearby ZIP codes
51041 Orange City (5.3 mi)
51022 Granville (7.5 mi)
51238 Hospers (8.2 mi)
51036 Maurice (10.4 mi)
51050 Remsen (13.2 mi)
51250 Sioux Center (13.8 mi)
51234 Boyden (14.1 mi)
51231 Archer (14.8 mi)
51201 Sheldon (15 mi)
51046 Paullina (16.5 mi)
51027 Ireton (16.8 mi)
51239 Hull (17 mi)
Demographics
updated 05/2026
| Population | |
|---|---|
| Total population | 1,761 |
| Population density | 32 / sq mi |
| State FIPS | 19 |
| County FIPS | 167 |
| Geography | |
|---|---|
| Land area | 54.36 sq mi |
| Water area | 0.03 sq mi |
| Latitude | 42.9826 |
| Longitude | -95.9896 |
| Timezone | Central (CT) |
| Area code | 712 |
Total population by age
Gender
Race & ethnicity
Economics
updated 05/2026
Household income
| Income range | This ZIP | County avg | State avg |
|---|---|---|---|
| Under $50k | 23.2% | 30.7% | 40.1% |
| $50k – $100k | 39.5% | 42.1% | 33.4% |
| $100k – $200k | 35.5% | 22.2% | 21.5% |
| Over $200k | 1.8% | 5.0% | 5.0% |
Demographics & statistics
1,761
Population
32
People per sq mi
35.0
Median age
$85,536
Median household income
$39,844
Per capita income
$215,800
Median home value
$695
Median monthly rent
88.4%
Home ownership
1.9%
Poverty rate
1.8%
Unemployment
654
Housing units
23.7%
Bachelor's or higher
Age distribution
Male
Female
52
Under 5
55
91
5–9
96
24
10–14
25
64
15–19
67
102
20–24
107
96
25–34
101
84
35–44
88
50
45–54
52
77
55–59
81
77
60–64
81
74
65–74
77
49
75–84
52
19
85+
20
← Male
Female →
Age summary
| Group | Count | % |
|---|---|---|
| Under 18 | 421 | 23.9% |
| 18 and over | 1,340 | 76.1% |
| 65 and over | 291 | 16.5% |
| Median age | 35.0 years | |
Race & ethnicity
White
95.8%
Two or more races
2%
Hispanic or Latino
1%
Asian
0.8%
Black or African American
0.2%
Other race
0.2%
| Group | Count | % |
|---|---|---|
| White | 1,704 | 95.8% |
| Two or more races | 35 | 2% |
| Hispanic or Latino | 18 | 1% |
| Asian | 15 | 0.8% |
| Black or African American | 4 | 0.2% |
| Other race | 3 | 0.2% |
Household income
| Income range | This ZIP | County avg | State avg |
|---|---|---|---|
| Under $50k | 23.2% | 30.7% | 40.1% |
| $50k – $100k | 39.5% | 42.1% | 33.4% |
| $100k – $200k | 35.5% | 22.2% | 21.5% |
| Over $200k | 1.8% | 5.0% | 5.0% |
Under $10k
0.7%
$10k–$15k
1.5%
$15k–$25k
2.4%
$25k–$35k
7.6%
$35k–$50k
12.8%
$50k–$75k
15.8%
$75k–$100k
16.5%
$100k–$150k
30.4%
$150k–$200k
4.9%
$200k+
7.4%
| Range | % of households |
|---|---|
| Under $10k | 0.7% |
| $10k–$15k | 1.5% |
| $15k–$25k | 2.4% |
| $25k–$35k | 7.6% |
| $35k–$50k | 12.8% |
| $50k–$75k | 15.8% |
| $75k–$100k | 16.5% |
| $100k–$150k | 30.4% |
| $150k–$200k | 4.9% |
| $200k+ | 7.4% |
| Median income | $85,536 |
Housing
Home values
Under $50k
4.2%
$50k–$100k
15.0%
$100k–$150k
15.0%
$150k–$200k
10.4%
$200k–$300k
24.2%
$300k–$500k
27.4%
$500k–$1M
3.7%
Housing overview
| Metric | Value |
|---|---|
| Median home value | $215,800 |
| Median rent / month | $695 |
| Owner occupied | 88.4% |
| Renter occupied | 11.6% |
| Vacant | 8.2% |
| Single-family detached | 84.7% |
| Large apartment buildings | 0.0% |
| Mobile homes | 1.8% |
| Median rooms | 7.5 |
| Avg household size (owned) | 2.79 |
Year built
| Era | % |
|---|---|
| 2020 or later | 0.0% |
| 2010–2019 | 5.7% |
| 2000–2009 | 9.3% |
| 1990–1999 | 8.6% |
| 1980–1989 | 5.1% |
| 1970–1979 | 21.6% |
| 1960–1969 | 15.2% |
| 1950–1959 | 4.9% |
| 1940–1949 | 2.6% |
| 1939 or earlier | 27.0% |
Bedrooms
| Size | % of units |
|---|---|
| No bedroom (studio) | 2.2% |
| 1 bedroom | 4.0% |
| 2 bedrooms | 15.6% |
| 3 bedrooms | 32.8% |
| 4 bedrooms | 34.4% |
| 5+ bedrooms | 11.1% |
Vehicles per household
| Vehicles | % of households |
|---|---|
| No vehicle | 0.4% |
| 1 vehicle | 24.4% |
| 2 vehicles | 42.6% |
| 3 or more | 32.6% |
Heating fuel
| Fuel type | % |
|---|---|
| Utility gas | 43.6% |
| Electricity | 47.6% |
| Propane / LP gas | 6.1% |
| Wood | 0.6% |
Households & families
| Household type | Count | % |
|---|---|---|
| Married-couple family | 479 | 71.3% |
| Cohabiting couple | 52 | 7.7% |
| Male householder, no spouse | 78 | 11.6% |
| Female householder, no spouse | 63 | 9.4% |
| Households with children under 18 | 198 | 29.5% |
| Households with seniors (65+) | 186 | 27.7% |
| Average household size | 2.62 | |
Marital status
| Status | Male | Female |
|---|---|---|
| Never married | 28.8% | 19.7% |
| Married | 66.6% | 72.5% |
| Separated | 1.4% | 1.4% |
| Widowed | 1.2% | 5.3% |
| Divorced | 1.9% | 1.1% |
Education
Less than 9th grade
1.9%
Some HS, no diploma
3.8%
HS graduate
31.1%
Some college, no degree
26.3%
Associate's degree
13.1%
Bachelor's degree
19.7%
Graduate / professional
4.1%
| Metric | % |
|---|---|
| HS diploma or higher | 94.2% |
| Bachelor's or higher | 23.7% |
School enrollment (ages 3–17)
| Type | Count | % |
|---|---|---|
| Nursery / preschool | 42 | 12.3% |
| Kindergarten | 26 | 7.6% |
| Elementary school | 124 | 36.3% |
| High school | 103 | 30.1% |
| College / grad school | 47 | 13.7% |
Employment
Industry of employment
Education & healthcare
21.9%
Manufacturing
15.7%
Retail trade
14.6%
Construction
8.3%
Agriculture & mining
7.8%
Finance & real estate
6.9%
Public administration
5.1%
Professional & management
4.7%
Transportation & utilities
4.4%
Other services
4.4%
Information
2.8%
Arts, food & hospitality
2.6%
Wholesale trade
0.6%
Occupation
| Category | % |
|---|---|
| Management, business & arts | 46.6% |
| Service | 10.5% |
| Sales & office | 12.4% |
| Natural resources & construction | 18.3% |
| Production & transportation | 12.1% |
Employment type
| Type | % |
|---|---|
| Private sector | 72.9% |
| Government | 14.0% |
| Self-employed | 12.8% |
| Unpaid family workers | 0.2% |
Commute
| Method | % |
|---|---|
| Drive alone | 82.6% |
| Carpool | 8.5% |
| Public transit | 0.5% |
| Walk | 0.5% |
| Work from home | 6.7% |
| Other means | 1.3% |
| Avg commute (minutes) | 13.3 |
Poverty
All people
1.9%
Under 18 years
2.9%
18 and over
1.6%
Married-couple families
0.0%
Female-led households
48.0%
Income support
| Source | % of households |
|---|---|
| Social Security | 29.8% |
| Retirement income | 23.2% |
| Supplemental Security | 6.4% |
| Cash public assistance | 2.1% |
| Food stamps / SNAP | 2.2% |
Health indicators
| Condition | % |
|---|---|
| Obesity | 35.4% |
| High blood pressure | 30.6% |
| High cholesterol | 30.3% |
| Diabetes | 8.4% |
| Heart disease | 5.4% |
| Stroke | 2.5% |
| Asthma | 8.8% |
| Arthritis | 22.2% |
| Kidney disease | 2.4% |
| Pulmonary disease | 5.5% |
| Cancer | 6.3% |
| Behavior / access | % |
|---|---|
| Smoking | 15.8% |
| Binge drinking | 21.1% |
| No physical activity | 21.8% |
| Less than 7 hrs sleep | 28.6% |
| Depression | 16.1% |
| Fair or poor health | 10.4% |
| Poor mental health | 12.8% |
| Poor physical health | 8.3% |
| No health insurance | 8.8% |
| Visited doctor (checkup) | 74.2% |
| Visited dentist | 71.2% |
| Cholesterol screening | 88.5% |
| Teeth loss | 11.9% |
Veterans & disability
| Veterans | Count | % |
|---|---|---|
| Civilian veterans | 39 | 2.9% |
| Disability | % |
|---|---|
| Any disability | 11.2% |
| Under 18 | 4.5% |
| 18–64 years | 9.8% |
| 65 and over | 26.1% |
Health insurance coverage
| Type | % |
|---|---|
| Private insurance | 82.9% |
| Public insurance | 28.8% |
| No insurance | 1.4% |
| Uninsured under 19 | 1.3% |
Language & origin
Language spoken at home (age 5+)
| Language | Count | % |
|---|---|---|
| English only | 1,654 | 93.9% |
| Spanish | 32 | 1.9% |
| Other Indo-European | 29 | 1.8% |
| Asian & Pacific Islander | 0 | 0.0% |
| Other languages | 3 | 0.2% |
Place of birth & citizenship
| Origin | Count | % |
|---|---|---|
| Native born (US) | 1,697 | 96.4% |
| Born in same state | 1,695 | 96.3% |
| Born in different state | 1,360 | 77.2% |
| Foreign born | 2 | 0.1% |
| Naturalized citizen | 64 | 3.6% |
| Not a US citizen | 35 | 54.7% |
Ancestry
| Ancestry | Count | % |
|---|---|---|
| English | 495 | 28.1% |
| Italian | 119 | 6.8% |
| French | 90 | 5.1% |
| Arab | 90 | 5.1% |
| Ancestry | Count | % |
|---|---|---|
| Polish | 52 | 3% |
| German | 48 | 2.7% |
| Dutch | 16 | 0.9% |
Technology access
| Metric | % of households |
|---|---|
| Computer access | 38.2% |
| Internet access | 93.9% |
Source: U.S. Census Bureau, American Community Survey 2025 estimates.
Frequently asked questions about ZIP code 51003
What city is ZIP code 51003 in?
ZIP code 51003 is primarily assigned to Alton, Iowa.
What county is ZIP code 51003 in?
ZIP code 51003 falls within Sioux County, Iowa.
Is ZIP code 51003 mostly owner-occupied?
88% of occupied units in ZIP code 51003 are owner-occupied, well above the national average.
What is the population of ZIP code 51003?
ZIP code 51003 has an estimated population of 1,761 residents, with a density of 32 people per square mile.
What is the typical home value in ZIP code 51003?
The median home value in ZIP code 51003 is $215,800.
What is the median household income in ZIP code 51003?
The median household income in ZIP code 51003 is $85,536, above the national median of ~$75,000.
What timezone is ZIP code 51003 in?
ZIP code 51003 observes the CST timezone.