| City: | Keymar, Maryland |
| City Alias: | Detour, Middleburg |
| Counties: | Carroll County [Primary] Frederick County |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 12:35:31 AM |
| Population: | 2,870 [See All] |
| Area Codes: | 443 / 410 / 667 |
| Classification: | Standard [Normal Street Delivery] |
| Coordinates: | 39.5973, -77.2478 |
| Land Area: | 35.173 sq mi |
| Quick Link: |
ZIP Code 21757 has 2,870 residents and 1,093 households (average 2.60 persons per household). The median age is 47.7 years, significantly older than the state (38.8) and significantly older than the nation (38.8). The gender split is 51.2% male and 48.8% female, which is higher than the state male share (48.2%), making this a male-majority area. Largest groups are White (91.2%, much higher than the state average of 48.7% and well above the national average of 61.6%) and Hispanic or Latino (2.9%); Hispanic or Latino residents make up 2.9%, which is much lower than the national average (18.7%).
Explore More: Population Over Time By Age & Gender By Race By Gender Nativity & Citizenship
| 2020 Population: | 2,870Source: Census DHC |
| 2023 ACS Population Estimate: | 2,810Source: Census ACS |
| 2025 ZC Population Estimate: | 2,831Source: ZIP-Codes.com |
| Population Density: | 81.6 people per sq mile |
| Average Income: | $98,520Source: Census ACS |
| Households: | 1,093Source: Census DHC |
| Average House Value: | $414,300Source: Census ACS |
| Persons Per Household: | 2.60Source: Census DHC |
| Average Family Size: | 2.70Source: Census ACS |
| Group | 2010 | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Census ACS Population Estimate | -- | 2,871 | 2,829 | 2,715 | 2,961 | 3,054 | 3,296 | 3,371 | 3,192 | 2,793 | 2,753 | 2,604 | 2,722 | 2,810 |
| Decennial Census | 3,036 | -- | -- | -- | -- | -- | -- | -- | -- | -- | 2,870 | -- | -- | -- |
Median Age: 47.7
Male Median Age: 47.1
Female Median Age: 48.7
| Group | < 5 | 5-9 | 10-14 | 15-19 | 20-24 | 25-29 | 30-34 | 35-39 | 40-44 | 45-49 | 50-54 | 55-59 | 60-64 | 65-69 | 70-74 | 75-79 | 80-84 | 85+ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Male | 76 | 85 | 93 | 107 | 52 | 79 | 80 | 70 | 73 | 79 | 134 | 125 | 134 | 82 | 79 | 61 | 45 | 16 |
| Female | 63 | 74 | 84 | 99 | 55 | 83 | 80 | 63 | 55 | 68 | 107 | 150 | 124 | 94 | 79 | 53 | 33 | 36 |
| Total | 139 | 159 | 177 | 206 | 107 | 162 | 160 | 133 | 128 | 147 | 241 | 275 | 258 | 176 | 158 | 114 | 78 | 52 |
| White: | 2,618 | 92.94% |
| Black: | 63 | 2.24% |
| Hispanic:* | 84 | 2.98% |
| Asian: | 18 | 0.64% |
| American Indian: | 14 | 0.50% |
| Hawaiian: | 1 | 0.04% |
| Other: | 19 | 0.67% |
| Total: | 2,817 | 100% |
| Gender | Count | % | Median Age |
|---|---|---|---|
| Males: | 1,470 | 51.22% | 47.1 years |
| Females: | 1,400 | 48.78% | 48.7 years |
| Total: | 2,870 | 100% | 47.7 years |
| Native, born in the United States: | 2,668 | 94.95% |
| Native, born in PR, Island Areas, or abroad: | 36 | 1.28% |
| Foreign born, naturalized U.S. citizen: | 83 | 2.95% |
| Foreign born, not a U.S. citizen: | 23 | 3.77% |
| Total Population: | 2,810 | 100% |
| Total Native Population: | 2,704 | 96.23% |
| Total Foreign-born Population: | 106 | 3.77% |
In 2023, the Median household income is $98,520, which is considerably higher than the national median ($78,538), is up $34,277 (53.4%) since 2011 and above its 2019 pre-pandemic level by $17,635. Family households earn a median of $110,625 versus $54,750 for nonfamily households (a difference of $55,875). By gender, male median income is $55,302 and female is $50,762, which is well under the state female median ($68,044), with a current gap of $4,540 that has widened from 2011 to 2023. The labor-force participation rate is 70.4%, which is above the national rate (63.5%). The unemployment rate is 2.9%, which is much lower than the national rate (5.2%). The largest occupation group is Management (36.6%).
Explore More: Income Over Time Household Income Employment Status By Occupation
| Income Type | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Household Income | $64,243 | $65,515 | $72,572 | $75,536 | $75,771 | $76,298 | $78,514 | $77,917 | $80,885 | $83,750 | $85,862 | $96,250 | $98,520 |
| Median Family Income | $80,417 | $83,631 | $74,647 | $76,169 | $77,181 | $78,615 | $82,537 | $93,558 | $98,125 | $105,625 | $109,485 | $113,214 | $110,625 |
| Median NonFamily Income | $36,983 | $36,500 | $40,000 | $43,190 | $39,464 | $35,938 | $37,000 | $40,347 | $45,809 | $51,667 | $44,917 | $56,071 | $54,750 |
| Median Male Income | $44,643 | $46,660 | $42,143 | $43,261 | $45,208 | $50,341 | $51,250 | $56,831 | $58,113 | $58,994 | $57,143 | $54,583 | $55,302 |
| Median Female Income | $42,639 | $44,632 | $43,578 | $43,252 | $42,500 | $41,500 | $44,021 | $37,813 | $46,250 | $50,000 | $51,923 | $49,667 | $50,762 |
| Employed: | 1,543 | 68.33% |
| Unemployed: | 46 | 2.04% |
| Not In Labor Force: | 669 | 29.63% |
| Total: | 2,258 | 100% |
| Management, business, science, and arts: | 565 | 36.62% |
| Service: | 128 | 8.30% |
| Sales and Office: | 320 | 20.74% |
| Natural resources, construction, and maintenance: | 349 | 22.62% |
| Production, transportation, and material moving: | 181 | 11.73% |
| Total Civilian Employed Population: | 1,543 | 100% |
In 2023, the median home value is $414,300, which is markedly greater than the national median ($303,400), is up $119,800 (40.68%) since 2011 and above its 2019 pre-pandemic level by $127,000. The median gross rent is $1,345, which is much lower than the state median ($1,662), is up $295 (28.10%) since 2011 and above its 2019 pre-pandemic level by $184. Of occupied housing, owners make up 82.49% (65.72% with a mortgage, 34.28% free-and-clear) and renters 17.51% - making this ZIP Code more home ownership than the state and under national rental averages. The vacancy rate is 5.40%, which is much lower than the national rate (10.43%).
Explore More: Compare Home Value Home Value Over Time Rent & Over Time Housing Occupancy
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Home Value | $294,500 | $278,000 | $298,500 | $288,600 | $277,400 | $269,900 | $279,700 | $272,900 | $287,300 | $297,700 | $331,900 | $425,000 | $414,300 |
| Less than $500: | 0 | 0.00% |
| $500 to $999: | 11 | 5.88% |
| $1,000 to $1,499: | 102 | 54.55% |
| $1,500 to $1,999: | 17 | 9.09% |
| $2,000 to $2,499: | 34 | 18.18% |
| $2,500 to $2,999: | 0 | 0.00% |
| $3,000 or more: | 0 | 0.00% |
| No Rent: | 23 | 12.30% |
| Total: | 187 | 100% |
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Rent | $1,050 | $1,060 | $1,146 | $1,188 | $1,213 | $1,170 | $1,277 | $1,220 | $1,161 | $1,148 | $1,139 | $1,331 | $1,345 |
| Owner Occupied (with mortgage): | 579 | 54.21% |
| Owner Occupied (free and clear, no mortgage): | 302 | 28.28% |
| Renter Occupied: | 187 | 17.51% |
| Total Occupied Housing Units: | 1,068 | 100% |
| Occupied Housing Units: | 1,068 | 94.60% |
| Vacant Housing Units (not graphed): | 61 | 5.40% |
| Total Housing Units: | 1,129 | 100% |
| Single-Family Units: | 1,062 | 94.07% |
| Multi-Family Units: | 59 | 5.23% |
| Other Units: | 8 | 0.71% |
| Total Housing Units: | 1,129 | 100% |
In 2023, 26.90% of adults (25+) have a bachelor's degree or higher, which is markedly below the state rate (42.70%). High school or higher is 92.30%, which is comparable to the national rate (89.40%). The uninsured rate is 2.20%, which is far lower than the national rate (8.60%). Private coverage is 85.30%, which is well above the national rate (67.30%). The share of people in poverty is 0.00%, which is far lower than the national rate (8.70%), down 9.30 percentage points since 2011 and below its 2019 pre-pandemic level by 3.20 percentage points. This points to a pronounced improvement in local conditions - rising incomes, firmer consumer demand, and a stronger tax base. Among residents ages 3+, the largest enrollment group is elementary (48.16%). College enrollment is 22.61%, which is on par with the state rate (28.00%), meaning the community mirrors broader higher-education participation.
Explore More: Educational Attainment Health Insurance Poverty Over Time School Enrollment
| Less than 9th grade: | 86 | 4.32% |
| 9th to 12th grade, no diploma: | 67 | 3.37% |
| High school graduate (includes equivalency): | 794 | 39.88% |
| Some college, no degree: | 404 | 20.29% |
| Associate's degree: | 105 | 5.27% |
| Bachelor's degree: | 289 | 14.52% |
| Graduate or professional degree: | 246 | 12.36% |
| Total: | 1,991 | 100% |
| High school or higher: | 1,838 | 92.32% |
| Bachelor's degree or higher: | 535 | 26.87% |
| Private Insurance: | 2,375 | 72.14% |
| Public Insurance: | 856 | 26.00% |
| No Insurance: | 61 | 1.85% |
| Total: | 3,292 | 100% |
| Has Health Insurance: | 3,231 | 98.15% |
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| % of People in Poverty | 9.3% | 6.2% | 6.3% | 1.8% | 1.7% | 1.1% | 1.7% | 2.7% | 3.2% | 4.5% | 4.2% | 0.8% | 0.0% |
Note: Counts of Families & People in poverty are not published at the ZIP Code level due to small sample sizes. Percentages shown are survey estimates from the American Community Survey (ACS). They may differ from official poverty statistics. The U.S. Census Bureau defines poverty status by comparing a family's or individual's total income with federal poverty thresholds that vary by family size and composition.
| Nursery School, Preschool: | 92 | 16.91% |
| Kindergarten: | 5 | 0.92% |
| Elementary school (grades 1-8): | 262 | 48.16% |
| High school (grades 9-12): | 62 | 11.40% |
| College or graduate school: | 123 | 22.61% |
| Total: | 544 | 100% |
| Early Childhood: | 97 | 17.83% |
| K-12 (Primary & Secondary School): | 329 | 60.48% |
ZIP Code 21757 supports both business and residential activity. According to the Business Census (2023), there are 64 business establishments, employing about 457 people with an annual payroll of $24,356,000. USPS data shows 1,089 residential mailboxes and 24 business mailboxes, reflecting local delivery coverage.
| # Residential Mailboxes: | 1,089Source: USPS |
| # Business Mailboxes: | 24Source: USPS |
| Total Delivery Receptacles: | 1,186Source: USPS |
| Single Family Delivery Units: | 1,089Source: USPS |
| Multi Family Delivery Units: | 0Source: USPS |
| # of Businesses: | 64Source: CBP |
| 1st Quarter Payroll: | $5,407,000Source: CBP |
| Annual Payroll: | $24,356,000Source: CBP |
| # of Employees: | 457Source: CBP |
ZIP Code 21757 is located in Carroll County, Maryland, within the Baltimore-Columbia-Towson, MD Metropolitan Statistical Area (CBSA 12580) and Maryland's 2nd and 6th Congressional Districts. This Metro area has a population of 2,839,409 people, about 0.10% of whom live in ZIP Code 21757. It covers 35.173 sq mi of land and a water area of 0.094 sq mi.
| CBSA Name: | Baltimore-Columbia-Towson, MDSource: Census |
| CBSA Number: | 12580Source: Census |
| CBSA Type: | MetroSource: Census |
| CBSA Division: | --Source: Census |
| CBSA Population: | 2,839,409Source: Census |
| MSA: | Washington-Baltimore, DC-MD-VA-WV CMSASource: Census |
| Land Area: | 35.173 sq miSource: Census |
| Water Area: | 0.094 sq miSource: Census |
| Congressional District: | 02,06Source: USPS |
| Congressional Land Area: | 348.88, 1950.26 sq miSource: Census |
| PMSA: | Baltimore, MD PMSASource: Census |
| Intro Date: | < 2004-10Source: ZIP-Codes.com |
| Place FIPS Code: | --Source: Census |
| Place Name: | --Source: Census |
ZIP Code 21757 is in the Frederick County Public Schools, which serves grades Pre-Kindergarten thru 12th. There are 1 public schools and 1 private school(s) in this ZIP Code. It also has 6 colleges, universities or post secondary education institutions nearby which would be a short commute to.
Our sources include trusted federal and licensed data from the United States Postal Service, U.S. Census Bureau, U.S. Geological Survey, Centers for Medicare & Medicaid Services, and the National Center for Education Statistics, along with proprietary datasets created by ZIP-Codes.com. Data last updated on October 1, 2025.