Mount Airy, MD 21771 ZIP Code Profile


ZIP Code 21771: Basic Data & USPS Preferred City Name

Preferred Name, USPS
Mount Airy, MD 21771

  • ZIP Code Type: STANDARD
  • County: Frederick County
  • Centroid: Latitude 39.388, Longitude -77.148
  • Time Zone: Eastern Time Zone (UTC -5 hours)
  • Observes DST: Yes

ZIP Code 21771 has segments in 4 Counties / Independent Cities (Carroll, Frederick, Howard, Montgomery).

  • Businesses Addresses: 749
  • PO Box Addresses: 340
  • Residential Addresses: 10,610
    • Multi-Family Addresses: 105
    • Single Family Addresses: 10,505

The ZIP Code maps and database are updated 4 times per year.
Database updated: May 1, 2018, Maps updated: February 1, 2018.

EXTREMELY LOCAL Demographic Data

Address Based Hyperlocal Data Input an address and get data & demographics for the pertinent census block group (CBG), a searchable map and a customized directory. The CBG is the smallest geographical unit used by the Census Bureau for reporting demographic data.


21771 ZIP Code Map

Search the map for:

Mount Airy, MD 21771 Data & Demographics (As of July 1, 2017)


Total Population 31,051
Daytime Population: Workers 7,414
Daytime Population: Residents 14,011
Total Daytime Population (TDP) 21,425
Ratio TDP/Total Population1 0.69
Population in Households 30,878
Population in Familes 27,953
Population in Group Qrtrs 173
Population Density2 375
Diversity Index3 24


Median Household Income $108,114
Average Household Income $131,727
Per Capita Income $43,971


Total Housing Units 10,658 (100%)
Owner Occupied HU 9,297 (87.2%)
Renter Occupied HU 1,020 ( 9.6%)
Vacant Housing Units 341 ( 3.2%)
Median Home Value $422,613
Average Home Value $452,536


Total Households 10,317
Average Household Size 2.99
Family Households 8,461
Average Family Size 3
  1. If the ratio of the TDP to Total Population is greater than 1, the location gains population during the day when commuting workers are present. If the ratio is less than 1, the location is more of a bedroom community where people commute to another place for work.
  2. Population Density = Total Population per square mile.
  3. The Diversity Index is a scale of 0 to 100 that represents the likelihood that two persons, chosen at random from the same area, belong to different race or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.


2010-2017 2017-2022
Population 0.57% 0.68%
Households 0.53% 0.65%
Families 0.44% 0.59%
Median Household Income   1.05%
Per Capita Income   2.05%

Mount Airy, MD 21771 - Peer Comparisons by Rank and Percentile

The table below compares 21771 to the other 456 ZIP Codes in Maryland by rank and percentile using July 1, 2017 data. The location Ranked # 1 has the highest value. A location that ranks higher than 75% of its peers would be in the 75th percentile of the peer group.

Variable Description Rank Percentile
Total Population # 76 84th
Population Density # 234 49th
Diversity Index # 343 25th
Median Household Income # 82 82nd
Per Capita Income # 128 72nd

Additional comparisons and rankings can be made with a VERY EASY TO USE Maryland Census Data Comparison Tool.

Maryland Research Tools

Maryland Census Data Comparison Tool

Compare Maryland Census Data
Highest or Lowest: