🇺🇸 United States ZIP Code

STANDARD

18104

Allentown

ZIP Code 18104 is a standard zip code serving Allentown, Allentown, Pennsylvania (PA), in Lehigh County, United States. It has an estimated population of 43,236 with a median household income of $67,929. The area falls within the America/New_York timezone.

Median Household Income vs. National Average

Location

Country: 🇺🇸 United States
State / Province: Pennsylvania (PA)
County: Lehigh
City: Allentown
Timezone: America/New_York

Coordinates

Latitude: 40.601800
Longitude: -75.522500

Geographic Details

Land Area: 23.10 mi²
Water Area: 0.21 mi²
Population Density: 1872.0 people per mi² (80th percentile)
Bounding Box: 40.665307°N, 40.565119°S, -75.482433°E, -75.602358°W

With 43,236 residents spread across 23.10 square miles, this area has a population density of 1872.0 people per square mile.

Demographics

43,236

Population

95th percentile

$67,929

Median Income

80th percentile

$214,100

Median Home Value

75th percentile

23.10 mi²

Land Area

The median household income in 18104 is $67,929, and the median home value is $214,100. This places the area in the top 25% nationally for household income.

Housing

17,599

Total Units

16,718

Occupied Units

95.0%

Occupancy Rate

Nearby ZIP Codes

Other zip codes in Allentown, PA.

18101

Allentown

18102

Allentown

18103

Allentown

18105

Allentown

18106

Allentown

18109

Allentown

18195

Allentown

Similar ZIP Codes in Pennsylvania

ZIP codes with similar median household income in Pennsylvania.

19003

Ardmore

$76,496

19547

Oley

$72,292

19428

Conshohocken

$75,136

17364

Thomasville

$60,179

15321

Cecil

$70,568

18211

Andreas

$76,010

19030

Fairless Hills

$61,776

17070

New Cumberland

$62,909

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.