Keymar, MD 21757 ZIP Code Profile

Related Place Profiles:
Detour, MD | Keymar, MD | Middleburg, MD

ZIP Code 21757: Basic Data & USPS Preferred City Name

Preferred Name, USPS
Keymar, MD 21757

Acceptable Alternative
Detour, MD 21757
Middleburg, MD 21757

  • ZIP Code Type: STANDARD
  • County: Carroll County
  • Centroid: Latitude 39.601, Longitude -77.254
  • Time Zone: Eastern Time Zone (UTC -5 hours)
  • Observes DST: Yes

ZIP Code 21757 has segments in 2 Counties / Independent Cities (Carroll, Frederick).

  • Businesses Addresses: 44
  • PO Box Addresses: 67
  • Residential Addresses: 1,047
    • Multi-Family Addresses: 0
    • Single Family Addresses: 1,047

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.


21757 ZIP Code Map

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Keymar, MD 21757 Data & Demographics (As of July 1, 2017)


Total Population 3,076
Daytime Population: Workers 485
Daytime Population: Residents 1,433
Total Daytime Population (TDP) 1,918
Ratio TDP/Total Population1 0.62
Population in Households 3,042
Population in Familes 2,618
Population in Group Qrtrs 34
Population Density2 88
Diversity Index3 18


Median Household Income $68,138
Average Household Income $85,448
Per Capita Income $31,522


Total Housing Units 1,184 (100%)
Owner Occupied HU 860 (72.6%)
Renter Occupied HU 260 (22.0%)
Vacant Housing Units 64 ( 5.4%)
Median Home Value $319,196
Average Home Value $353,547


Total Households 1,120
Average Household Size 2.72
Family Households 862
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 0.47% 0.6%
Households 0.49% 0.58%
Families 0.37% 0.51%
Median Household Income   2.51%
Per Capita Income   3.01%

Keymar, MD 21757 - Peer Comparisons by Rank and Percentile

The table below compares 21757 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 # 273 40th
Population Density # 369 19th
Diversity Index # 380 17th
Median Household Income # 268 41st
Per Capita Income # 287 37th

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

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