🇺🇸 United States ZIP Code

PO BOX

18631

Mifflinville

ZIP Code 18631 is a po box zip code serving Mifflinville, Mifflinville, Pennsylvania (PA), in Columbia County, United States. It has an estimated population of 1,286 with a median household income of $58,791. The area falls within the America/New_York timezone.

Median Household Income vs. National Average

Location

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

Coordinates

Latitude: 41.032300
Longitude: -76.308000

Geographic Details

Land Area: 1.72 mi²
Water Area: 0.16 mi²
Population Density: 749.0 people per mi² (75th percentile)
Bounding Box: 41.038232°N, 41.017868°S, -76.280698°E, -76.326834°W

With 1,286 residents spread across 1.72 square miles, this area has a population density of 749.0 people per square mile.

Demographics

1,286

Population

30th percentile

$58,791

Median Income

70th percentile

$145,000

Median Home Value

55th percentile

1.72 mi²

Land Area

The median household income in 18631 is $58,791, and the median home value is $145,000.

Housing

580

Total Units

541

Occupied Units

93.3%

Occupancy Rate

Similar ZIP Codes in Pennsylvania

ZIP codes with similar median household income in Pennsylvania.

16509

Erie

$56,680

16056

Saxonburg

$50,727

19033

Folsom

$63,216

18080

Slatington

$58,415

17214

Blue Ridge Summit

$52,112

19405

Bridgeport

$50,450

15215

Pittsburgh

$60,148

17552

Mount Joy

$62,131

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.