🇺🇸 United States ZIP Code

STANDARD

21231

Baltimore

ZIP Code 21231 is a standard zip code serving Baltimore, Baltimore, Maryland (MD), in Baltimore (city) County, United States. It has an estimated population of 15,748 with a median household income of $53,750. The area falls within the America/New_York timezone.

Median Household Income vs. National Average

Location

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

Coordinates

Latitude: 39.289200
Longitude: -76.590000

Geographic Details

Land Area: 0.87 mi²
Water Area: 0.15 mi²
Population Density: 18051.0 people per mi² (95th percentile)
Bounding Box: 39.298524°N, 39.276916°S, -76.583467°E, -76.602588°W

With 15,748 residents spread across 0.87 square miles, this area has a population density of 18051.0 people per square mile.

Demographics

15,748

Population

75th percentile

$53,750

Median Income

60th percentile

$269,800

Median Home Value

85th percentile

0.87 mi²

Land Area

The median household income in 21231 is $53,750, and the median home value is $269,800.

Housing

9,108

Total Units

7,640

Occupied Units

83.9%

Occupancy Rate

Nearby ZIP Codes

Other zip codes in Baltimore, MD.

21201

Baltimore

21202

Baltimore

21203

Baltimore

21205

Baltimore

21206

Baltimore

21209

Baltimore

21210

Baltimore

21211

Baltimore

21212

Baltimore

21213

Baltimore

Similar ZIP Codes in Maryland

ZIP codes with similar median household income in Maryland.

20770

Greenbelt

$59,857

20737

Riverdale

$59,427

20785

Hyattsville

$60,324

21869

Vienna

$51,833

21636

Goldsboro

$60,926

20745

Oxon Hill

$60,629

21211

Baltimore

$55,819

21811

Berlin

$60,676

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.