US > Maryland > Frederick County > Knoxville, MD 21758

21758 ZIP Code Profile, Map, Data & Demographics

Related Place Profiles:
Brunswick, MD | Knoxville, MD | Rosemont, MD
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ZIP Code 21758: Basic Data & USPS Preferred City Name

Preferred Name, USPS
Knoxville, MD 21758

Acceptable Alternative
Brunswick, MD 21758
Rosemont, MD 21758

  • ZIP Code Type: STANDARD
  • County: Frederick County
  • Centroid: Latitude 39.341, Longitude -77.654
  • Time Zone: Eastern Time Zone (UTC -5 hours)
  • Observes DST: Yes

ZIP Code 21758 has segments in 2 Counties / Independent Cities (Frederick, Washington).

  • Businesses Addresses: 30
  • PO Box Addresses: 4
  • Residential Addresses: 1,825
    • Multi-Family Addresses: 0
    • Single Family Addresses: 1,825

The ZIP Code maps and database are updated 4 times per year.
Database updated: October 1, 2025, Maps updated: May 1, 2024.

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Knoxville, MD 21758 Data & Demographics (As of July 1, 2025)

POPULATION

Total Population 4,853 (100%)
Population in Households 4,853 (100.0%)
Population in Families 4,135 (85.2%)
Population in Group Quarters1 0
Population Density 143
Diversity Index2 45
 
 

INCOME

Median Household Income $117,221
Average Household Income $141,303
% of Income for Mortgage4 28%
Per Capita Income $51,071
Wealth Index5 147
Socioeconomic Status Index6 Moderate (55.7)
 

HOUSING

Total HU (Housing Units) 1,855 (100%)
Owner Occupied HU 1,578 (85.1%)
Renter Occupied HU 176 ( 9.5%)
Vacant Housing Units 101 ( 5.4%)
Median Home Value $518,987
Average Home Value $580,550
Housing Affordability Index3 84
 

HOUSEHOLDS

Total Households 1,754
Average Household Size 2.77
Family Households 1,279
Average Family Size 3.00
NOTES
  1. Group Quarters - a place where people live or stay in a group living arrangement. Includes college residents halls, nursing facilities, military barracks, and correctional facilities.
  2. 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 races 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.
  3. The Housing Affordability Index base is 100 and represents a balance point where a resident with a median household income can normally qualify to purchase a median price home. Values above 100 indicate increased affordability, while values below 100 indicate decreased affordability.
  4. The % of Income for Mortgage quantifies the percentage of median household income dedicated to mortgage payments on a home priced at the median value (assuming a 30-year mortgage and a 20% down payment).
  5. The Wealth Index is based on a number of indicators of affluence including average household income and average net worth, but it also includes the value of material possessions and resources. It represents the wealth of the area relative to the national level. Values above or below 100 represent above-average wealth or below-average wealth compared to the national level.
  6. The Socioeconomic Index ranges from zero (lowest relative status) to 100 (highest relative status). This measure quantifies disparities in social position of an area's inhabitants and is built from a broad range of demographic, housing, and socioeconomic inputs. More information on this measure can be found in Esri's SEI tutorial.

GROWTH RATE / YEAR

 2020-2025 2025-2030
Population -0.18% 0.75%
Households -0.18% 0.77%
Families   1.49%
Median Household Income   1.98%
Per Capita Income   2.12%
Owner Occupied HU   0.93%

Knoxville, MD 21758 - Peer Comparisons by Rank and Percentile

The table below compares 21758 to the other 458 ZIP Codes in Maryland by rank and percentile using July 1, 2025 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 # 241 47th
Population Density # 322 30th
Median Household Income # 165 64th
Housing Affordability Index # 208 45th
Per Capita Income # 221 52nd
Diversity Index # 257 44th

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


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Frederick County


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