PlainZIP

Mount Airy, MD · standard

ZIP Code 21771

Frederick County, Maryland - Census ACS demographics, housing tenure, and business patterns, benchmarked against every US ZIP.

29,563
134/sq mi
$157,302
Median income
$556,200
Median home value
48.8%
Bachelor's or higher

The verdict

Mount Airy pairs a top-decile household income with upper-quartile home values, in a rural, homeowner-dominated area.

Top 3%
household income, US ZIPs
Top 11%
home value, US ZIPs
134
people per sq mi
94%
owner-occupied homes

Source: U.S. Census Bureau ACS 5-Year Estimates (2019–2023). Percentiles rank ZIP 21771 against every reporting US ZIP.

ZIP code 21771 is a densely settled ZIP (a standard USPS delivery area) in Mount Airy, Frederick County, Maryland, with 29,563 residents across 220.3 square miles, a density of 134 people per square mile, in the New York time zone.

ZIP 21771 skews affluent, with a median household income of $157,302 (38% above the Maryland average), while per-capita income is $60,220. 3.1% of residents live below the poverty line, and the unemployment rate reads 4.3%. The typical home here is valued at $556,200 (24% above the state average); renters pay a median of $2,252 monthly, and 94.0% of units are owner-occupied.

A solid share of residents have a four-year degree: 48.8% of adults hold a bachelor's degree or higher, the median age is 40.9, and the average commute is 36 minutes. To put 21771 in local context, 10 ZIP codes within roughly 10 miles appear further down this page alongside 6 additional ZIPs in Frederick County, for a geography-aware comparison.

Every figure on this page is sourced from the U.S. Census Bureau American Community Survey 5-Year Estimates (including median rent) and the FHFA House Price Index, no estimates, no proprietary scoring. Verify with Census →

Top industries in ZIP 21771

Top 5 sectors by establishment count in Mount Airy, MD

Which industries have the most business establishments in ZIP 21771.

establishments

What this shows Establishment counts come from the Census ZIP Code Business Patterns program, which counts physical business locations rather than employees or revenue.

Source U.S. Census Bureau · ZIP Code Business Patterns (ZBP) As of 2023

Source: U.S. Census Bureau, American Community Survey 5-Year Estimates + ZIP Code Business Patterns + FHFA HPI ACS demographics and median rent, ZBP business establishments, FHFA HPI for ZIP 21771, Mount Airy, MD · 2023 Census ACS 5-Year Estimates use a rolling 60-month sample for stable small-geography estimates; ZBP updated annually; FHFA HPI updated quarterly/annually.

Quick Facts

29,563

Population

220.3

Area (sq mi)

134

People / sq mi

New York

Time Zone

standard

ZIP Type

Neighborhood Scorecard
Get an A-F grade across income, safety, housing, rent, education, commute, and childcare for this ZIP code.
View Scorecard →

Who lives in ZIP 21771?

40.9

Median Age

50.6%

Male

49.4%

Female

8.4%

Foreign-Born

White 84.8%
African American 3.6%
Asian 1.4%
American Indian or Alaska Native 0.7%
Native Hawaiian or Pacific Islander 0.0%
Two or More Ethnicities 6.0%
Hispanic or Latino 8.3%

Hispanic or Latino is an ethnicity category from the Census Bureau and may overlap with other categories above.

Source: U.S. Census Bureau, ACS 5-Year Estimates (2023)

How much do residents earn?

$157,302

Median Household Income

+38% vs state

$60,220

Per Capita Income

3.1%

Poverty Rate

4.3%

Unemployment Rate

36.1 min

Mean Commute Time

How ZIP 21771 ranks nationally

Mount Airy, MD household income vs. every US ZIP code

Median household income, the full national distribution, with this ZIP marked

$157,302 Top 3% higher than 97% of 30,318 US ZIPs

$0–$20,000: 118 US ZIPs (0%). Below this entry. $20,000–$40,000: 1,573 US ZIPs (5%). Below this entry. $40,000–$60,000: 7,092 US ZIPs (23%). Below this entry. $60,000–$80,000: 9,980 US ZIPs (33%). Below this entry. $80,000–$100,000: 5,778 US ZIPs (19%). Below this entry. $100,000–$120,000: 2,855 US ZIPs (9%). Below this entry. $120,000–$140,000: 1,362 US ZIPs (4%). Below this entry. $140,000–$160,000: 686 US ZIPs (2%). This entry sits in this band. $160,000–$180,000: 364 US ZIPs (1%). Above this entry. $180,000–$200,000: 186 US ZIPs (1%). Above this entry. $200,000–$220,000: 324 US ZIPs (1%). Above this entry. This ZIP $0 $200K+ every reporting US ZIP, bucketed by value

Each bar is a $20K-wide band; taller bars hold more US ZIPs. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source U.S. Census Bureau, ACS 5-Year Estimates · 2019–2023

Source: U.S. Census Bureau, ACS 5-Year Estimates (2023)

What is the education profile here?

High School Graduate or Higher 69.2%
Bachelor's Degree or Higher 48.8%

Source: U.S. Census Bureau, ACS 5-Year Estimates (2023)

What does housing look like?

11,758

Total Housing Units

11,226

Occupied Units

532

Vacant Units

2.93

Avg Household Size

Occupancy Type

Owner 94.0%
Renter 6.0%

$556,200

Median Home Value

+24% vs state

$2,252

Median Rent

1988

Median Year Built

Source: U.S. Census Bureau, ACS 5-Year Estimates (2023)

How have home values changed over time?

FHFA House Price Index, annual appreciation data based on repeat sales and appraisals

+7.6%

YoY Change (2024)

269

HPI Index (2000 = 100)

+169%

Total Change Since 2000

Home values in ZIP 21771 have increased 7.6% over the past year (2024). Since 2000, this ZIP has seen +169% cumulative appreciation.

Year Annual Change HPI Index
2020 +2.6% 191
2021 +9.8% 209
2022 +11.9% 234
2023 +6.8% 250
2024 +7.6% 269

Source: Federal Housing Finance Agency (FHFA) House Price Index, All-Transactions, Five-Digit ZIP Codes (Developmental Index). Index base = 100 in year 2000. Data through 2024. ZIP codes with few transactions may show missing values.

What businesses operate in this ZIP?

Census Bureau data shows 759 business establishments in ZIP 21771, employing approximately 7,538 people with a combined annual payroll of $399,631,000.

759

Businesses

7,538

Employees

$399.6M

Annual Payroll

17

Industry Sectors

Industry Establishments % of Total
Construction 182 24.0%
Professional, scientific, and technical services 95 12.5%
Other services (except public administration) 72 9.5%
Administrative and support and waste management and remediation services 71 9.3%
Health care and social assistance 71 9.3%
Retail trade 70 9.2%
Accommodation and food services 48 6.3%
Real estate and rental and leasing 38 5.0%
Finance and insurance 30 4.0%
Wholesale trade 17 2.2%
Manufacturing 15 2.0%
Transportation and warehousing 13 1.7%
Arts, entertainment, and recreation 11 1.4%
Educational services 9 1.2%
Information 8 1.1%
Utilities 4 0.5%
Agriculture, forestry, fishing and hunting 3 0.4%

Source: U.S. Census Bureau, ZIP Code Business Patterns (ZBP), 2023. Employment figures may include noise for disclosure avoidance.

Nearby ZIP Codes

Want a side-by-side? Compare 21771 vs 21774 →

ZIP 21771 vs its nearest neighbors, by population

Resident population of this ZIP and the closest reporting ZIP codes within ~10 miles.

residents

What this shows Among its immediate neighbors, ZIP 21771 ranks the most populous - useful context the national average alone can't give.

Source U.S. Census Bureau · ACS 5-Year Estimates As of 2019–2023

ZIP 21771 vs its nearest neighbors, by median income

Median household income of this ZIP and the closest reporting ZIP codes within ~10 miles.

median income

What this shows By household income, ZIP 21771 ranks #7 of 9 neighboring ZIPs, local affluence varies block to block, not just metro to metro.

Source U.S. Census Bureau · ACS 5-Year Estimates As of 2019–2023
ZIP Code City Population Distance
21774 New Market, MD 11,662 6.5 mi
21770 Monrovia, MD 5,164 6.1 mi
21797 Woodbine, MD 8,839 6.2 mi
20872 Damascus, MD 13,104 7.8 mi
21776 New Windsor, MD 5,735 8.9 mi
21791 Union Bridge, MD 5,281 10.2 mi
21762 Libertytown, MD 249 7.7 mi
21723 Cooksville, MD 803 9.1 mi
21738 Glenwood, MD 3,268 10.5 mi
20871 Clarksburg, MD 13,130 11.4 mi

More ZIP Codes in Frederick County

21702 standard
Frederick, MD
Pop: 38,847
21701 standard
Frederick, MD
Pop: 35,293
21703 standard
Frederick, MD
Pop: 32,854
21704 standard
Frederick, MD
Pop: 13,321
21774 standard
New Market, MD
Pop: 11,662
21788 standard
Thurmont, MD
Pop: 11,622

Related Areas

Frederick County Mount Airy, MD Maryland

Frequently Asked Questions

What county is ZIP code 21771 in? ▼
ZIP code 21771 (Mount Airy) is located in Frederick County, Maryland. Frederick County contains multiple ZIP codes, see the full list at /counties/frederick-md.
What is the population of ZIP code 21771? ▼
ZIP code 21771 in Mount Airy, MD has a population of 29,563 according to the Census Bureau ACS 2023 estimates.
What is the median household income in ZIP 21771? ▼
The median household income in ZIP 21771 is $157,302, which is 106% above the national average of $76,288.
What is the average home value in ZIP 21771? ▼
The median home value in ZIP 21771 is $556,200, which is 100% above the national average of $278,155.
What is the demographic makeup of ZIP 21771? ▼
The largest racial group in ZIP 21771 is White at 84.8%. Hispanic or Latino residents make up 8.3% of the population.
How many businesses are in ZIP code 21771? ▼
ZIP code 21771 has 759 business establishments employing approximately 7,538 people, according to Census Bureau ZIP Code Business Patterns (ZBP) 2023 data.
What are the main industries in ZIP code 21771? ▼
The top industries by establishment count in ZIP 21771 are: Construction (182), Professional, scientific, and technical services (95), Other services (except public administration) (72). There are 17 industry sectors represented in total.
How have home values changed in ZIP code 21771? ▼
According to the FHFA House Price Index, home values in ZIP 21771 increased by 7.6% in 2024. Since 2000, home values in this ZIP have appreciated by approximately 169%. This is a developmental index based on repeat sales and appraisal data from Fannie Mae and Freddie Mac.
What is the education level in ZIP code 21771? ▼
In ZIP code 21771, 69.2% of residents aged 25+ have a high school diploma or higher, and 48.8% hold a bachelor's degree or higher. These figures come from the Census Bureau ACS 5-Year Estimates (2023).
What is the average commute time in ZIP 21771? ▼
The mean commute time for workers in ZIP code 21771 is 36.1 minutes according to Census ACS data. The national average is roughly 26 minutes, so commuters here spend more time traveling to work than typical.
What percentage of residents own vs. rent in ZIP 21771? ▼
In ZIP code 21771, approximately 94.0% of occupied housing units are owner-occupied and 6.0% are renter-occupied, based on Census ACS 2023 data.
What is the poverty rate in ZIP code 21771? ▼
The poverty rate in ZIP code 21771 is 3.1% according to Census Bureau ACS 2023 estimates. This measures the percentage of the population living below the federal poverty threshold.

Read our methodology to see how this data is sourced, computed, and verified.