PlainZIP

Knoxville, MD · standard

ZIP Code 21758

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

4,921
59/sq mi
$111,528
Median income
$424,600
Median home value
43.7%
Bachelor's or higher

The verdict

Knoxville pairs an upper-quartile household income with upper-quartile home values, in a rural, homeowner-dominated area.

Top 13%
household income, US ZIPs
Top 18%
home value, US ZIPs
59
people per sq mi
84%
owner-occupied homes

Source: U.S. Census Bureau ACS 5-Year Estimates (2019–2023). Percentiles rank ZIP 21758 against every reporting US ZIP.

ZIP code 21758 covers 84.0 square miles in Knoxville, Frederick County, Maryland (a standard USPS delivery area), with a modest 4,921 residents on file, a density of 59 people per square mile, in the New York time zone.

ZIP 21758 skews affluent, with a median household income of $111,528 (2% below the Maryland average), while per-capita income is $50,488. The poverty rate stands at 5.9% and the unemployment rate at 8.5%. The typical home here is valued at $424,600 (5% below the state average); renters pay a median of $1,770 monthly, and 84.4% of units are owner-occupied.

A solid share of residents have a four-year degree: 43.7% of adults hold a bachelor's degree or higher, the median age is 39, and the average commute is 36 minutes. To put 21758 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 21758

Top 5 sectors by establishment count in Knoxville, MD

Which industries have the most business establishments in ZIP 21758.

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 21758, Knoxville, 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

4,921

Population

84.0

Area (sq mi)

59

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 21758?

39.0

Median Age

51.5%

Male

48.5%

Female

7.9%

Foreign-Born

White 81.3%
African American 2.9%
Asian 2.0%
American Indian or Alaska Native 0.0%
Native Hawaiian or Pacific Islander 0.8%
Two or More Ethnicities 12.8%
Hispanic or Latino 9.0%

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?

$111,528

Median Household Income

-2% vs state

$50,488

Per Capita Income

5.9%

Poverty Rate

8.5%

Unemployment Rate

36.1 min

Mean Commute Time

How ZIP 21758 ranks nationally

Knoxville, MD household income vs. every US ZIP code

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

$111,528 Top 13% higher than 87% 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%). This entry sits in this band. $120,000–$140,000: 1,362 US ZIPs (4%). Above this entry. $140,000–$160,000: 686 US ZIPs (2%). Above this entry. $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 77.8%
Bachelor's Degree or Higher 43.7%

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

What does housing look like?

1,626

Total Housing Units

1,588

Occupied Units

38

Vacant Units

2.78

Avg Household Size

Occupancy Type

Owner 84.4%
Renter 15.6%

$424,600

Median Home Value

-5% vs state

$1,770

Median Rent

1979

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

-7.1%

YoY Change (2024)

223

HPI Index (2000 = 100)

+123%

Total Change Since 2000

Home values in ZIP 21758 have decreased 7.1% over the past year (2024). Since 2000, this ZIP has seen +123% cumulative appreciation.

Year Annual Change HPI Index
2020 +4.5% 167
2021 +10.6% 185
2022 +14.3% 211
2023 +13.8% 241
2024 -7.1% 223

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 59 business establishments in ZIP 21758, employing approximately 402 people with a combined annual payroll of $16,270,000.

59

Businesses

402

Employees

$16.3M

Annual Payroll

6

Industry Sectors

Industry Establishments % of Total
Construction 16 27.1%
Other services (except public administration) 12 20.3%
Professional, scientific, and technical services 10 16.9%
Administrative and support and waste management and remediation services 6 10.2%
Retail trade 4 6.8%
Accommodation and food services 4 6.8%

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 21758 vs 21716 →

ZIP 21758 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 21758 ranks #5 by population - useful context the national average alone can't give.

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

ZIP 21758 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 21758 ranks #4 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
21716 Brunswick, MD 4,885 3.3 mi
21718 Burkittsville, MD 151 3.6 mi
21779 Rohrersville, MD 983 5.5 mi
20180 Lovettsville, VA 6,549 5.7 mi
21755 Jefferson, MD 5,591 5.3 mi
21756 Keedysville, MD 3,612 7.4 mi
25432 Millville, WV 121 7.0 mi
25425 Harpers Ferry, WV 12,835 7.5 mi
21769 Middletown, MD 11,236 8.5 mi
21782 Sharpsburg, MD 4,097 9.1 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
21771 standard
Mount Airy, MD
Pop: 29,563
21704 standard
Frederick, MD
Pop: 13,321
21774 standard
New Market, MD
Pop: 11,662

Related Areas

Frederick County Knoxville, MD Maryland

Frequently Asked Questions

What county is ZIP code 21758 in? ▼
ZIP code 21758 (Knoxville) 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 21758? ▼
ZIP code 21758 in Knoxville, MD has a population of 4,921 according to the Census Bureau ACS 2023 estimates.
What is the median household income in ZIP 21758? ▼
The median household income in ZIP 21758 is $111,528, which is 46% above the national average of $76,288.
What is the average home value in ZIP 21758? ▼
The median home value in ZIP 21758 is $424,600, which is 53% above the national average of $278,155.
What is the demographic makeup of ZIP 21758? ▼
The largest racial group in ZIP 21758 is White at 81.3%. Hispanic or Latino residents make up 9.0% of the population.
How many businesses are in ZIP code 21758? ▼
ZIP code 21758 has 59 business establishments employing approximately 402 people, according to Census Bureau ZIP Code Business Patterns (ZBP) 2023 data.
What are the main industries in ZIP code 21758? ▼
The top industries by establishment count in ZIP 21758 are: Construction (16), Other services (except public administration) (12), Professional, scientific, and technical services (10). There are 6 industry sectors represented in total.
How have home values changed in ZIP code 21758? ▼
According to the FHFA House Price Index, home values in ZIP 21758 decreased by 7.1% in 2024. Since 2000, home values in this ZIP have appreciated by approximately 123%. 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 21758? ▼
In ZIP code 21758, 77.8% of residents aged 25+ have a high school diploma or higher, and 43.7% 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 21758? ▼
The mean commute time for workers in ZIP code 21758 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 21758? ▼
In ZIP code 21758, approximately 84.4% of occupied housing units are owner-occupied and 15.6% are renter-occupied, based on Census ACS 2023 data.
What is the poverty rate in ZIP code 21758? ▼
The poverty rate in ZIP code 21758 is 5.9% 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.