🇺🇸 United States ZIP Code

STANDARD

21157

Westminster

ZIP Code 21157 is a standard zip code serving Westminster, Westminster, Maryland (MD), in Carroll County, United States. It has an estimated population of 36,920 with a median household income of $71,826. The area falls within the America/New_York timezone.

Median Household Income vs. National Average

Location

Country: 🇺🇸 United States
State / Province: Maryland (MD)
County: Carroll
City: Westminster
Timezone: America/New_York

Coordinates

Latitude: 39.564200
Longitude: -76.980700

Geographic Details

Land Area: 76.64 mi²
Water Area: 0.18 mi²
Population Density: 482.0 people per mi² (70th percentile)
Bounding Box: 39.671715°N, 39.442188°S, -76.891717°E, -77.092616°W

With 36,920 residents spread across 76.64 square miles, this area has a population density of 482.0 people per square mile.

Demographics

36,920

Population

90th percentile

$71,826

Median Income

85th percentile

$307,700

Median Home Value

85th percentile

76.64 mi²

Land Area

The median household income in 21157 is $71,826, and the median home value is $307,700. This places the area in the top 25% nationally for household income.

Housing

14,399

Total Units

13,683

Occupied Units

95.0%

Occupancy Rate

Nearby ZIP Codes

Other zip codes in Westminster, MD.

21158

Westminster

Similar ZIP Codes in Maryland

ZIP codes with similar median household income in Maryland.

20906

Silver Spring

$72,354

21713

Boonsboro

$76,412

21918

Conowingo

$80,161

21673

Trappe

$64,846

21220

Middle River

$61,672

21651

Millington

$62,625

21623

Church Hill

$66,471

21778

Rocky Ridge

$78,158

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.