21757 ZIP Code — Keymar, MD

Carroll County, Maryland

ZIP code 21757 is located in Keymar, Maryland, within Carroll County. It covers approximately 35.17 square miles and serves a population of 2,722 residents. This is a standard ZIP code in the Eastern (ET) timezone, served by area code 443/410/667.

About ZIP code 21757

The housing stock consists of predominantly single-family detached homes. Most homes were built in the pre-1940, giving the area an established character. Median home value is $425,000. Owner-occupancy is high at 76%, well above the national average.

Median household income is $96,250. The poverty rate of 3% is below the national average. 39% of households receive Social Security income, suggesting a notable retiree or disability population.

The dominant occupation class is management, business, and professional, with education and healthcare as the leading industry. An above-average commute of 36 minutes suggests many residents work outside the immediate area.

Educational attainment is near the national average, with 30% of residents holding a bachelor's degree or higher.

Overall, ZIP code 21757 reflects a community defined by high homeownership and a significant Social Security-dependent population.

2,722

population

35.17

sq mi land

Standard

ZIP type

Eastern (ET)

timezone

21757 ZIP code map

Cities in ZIP code 21757

Below are the cities the US Postal Service accepts for ZIP code 21757. Using any city not on this list may result in mail delivery delays.

City	Status
Keymar	Acceptable
Keymar	Preferred

Nearby ZIP codes

21798 Woodsboro (4.5 mi) 21778 Rocky Ridge (4.7 mi) 21791 Union Bridge (5.5 mi) 21787 Taneytown (5.7 mi) 21727 Emmitsburg (7.2 mi) 21793 Walkersville (8.8 mi) 21788 Thurmont (9.4 mi) 21776 New Windsor (9.6 mi) 21701 Frederick (10.4 mi) 21158 Westminster (12.1 mi) 21780 Sabillasville (12.9 mi) 21774 New Market (12.9 mi)

Demographics updated 05/2026

Population
Total population	2,722
Population density	77 / sq mi
State FIPS	24
County FIPS	013

Geography
Land area	35.17 sq mi
Water area	0.09 sq mi
Latitude	39.5973
Longitude	-77.2478
Timezone	Eastern (ET)
Area code	443/410/667

Total population by age

Gender

Race & ethnicity

Economics updated 05/2026

Household income

Income range	This ZIP	County avg	State avg
Under $50k	19.0%	23.8%	28.2%
$50k – $100k	36.5%	26.3%	28.2%
$100k – $200k	35.7%	37.1%	30.1%
Over $200k	8.9%	12.8%	13.4%

Demographics & statistics

2,722

Population

People per sq mi

46.4

Median age

$96,250

Median household income

$44,296

Per capita income

$425,000

Median home value

$1,331

Median monthly rent

75.9%

Home ownership

2.7%

Poverty rate

3.8%

Unemployment

867

Housing units

29.9%

Bachelor's or higher

Age distribution

Male Female

Under 5

5–9

10–14

15–19

20–24

156

25–34

126

145

35–44

117

213

45–54

172

156

55–59

127

60–64

168

65–74

137

126

75–84

103

85+

← Male

Female →

Age summary

Group	Count	%
Under 18	518	19.0%
18 and over	2,204	81.0%
65 and over	559	20.5%
Median age	46.4 years

Race & ethnicity

White 91.9%

Two or more races 2.2%

Black or African American 1.9%

Asian 1.6%

American Indian / Alaska Native 1.3%

Hispanic or Latino 1.1%

Group	Count	%
White	2,530	91.9%
Two or more races	60	2.2%
Black or African American	53	1.9%
Asian	43	1.6%
American Indian / Alaska Native	36	1.3%
Hispanic or Latino	31	1.1%

Household income

Income range	This ZIP	County avg	State avg
Under $50k	19.0%	23.8%	28.2%
$50k – $100k	36.5%	26.3%	28.2%
$100k – $200k	35.7%	37.1%	30.1%
Over $200k	8.9%	12.8%	13.4%

Under $10k 3.0%

$15k–$25k 1.4%

$25k–$35k 2.5%

$35k–$50k 8.9%

$50k–$75k 20.7%

$75k–$100k 15.2%

$100k–$150k 27.4%

$150k–$200k 10.8%

$200k+ 10.2%

Range	% of households
Under $10k	3.0%
$15k–$25k	1.4%
$25k–$35k	2.5%
$35k–$50k	8.9%
$50k–$75k	20.7%
$75k–$100k	15.2%
$100k–$150k	27.4%
$150k–$200k	10.8%
$200k+	10.2%
Median income	$96,250

Housing

Home values

Under $50k 1.6%

$100k–$150k 1.6%

$150k–$200k 5.2%

$200k–$300k 17.5%

$300k–$500k 36.4%

$500k–$1M 21.3%

$1M+ 16.5%

Housing overview

Metric	Value
Median home value	$425,000
Median rent / month	$1,331
Owner occupied	75.9%
Renter occupied	24.1%
Vacant	6.4%
Single-family detached	92.6%
Large apartment buildings	2.2%
Mobile homes	2.4%
Median rooms	7.2
Avg household size (owned)	2.51

Year built

Era	%
2020 or later	0.0%
2010–2019	3.9%
2000–2009	11.6%
1990–1999	12.9%
1980–1989	10.2%
1970–1979	9.6%
1960–1969	8.7%
1950–1959	2.8%
1940–1949	5.8%
1939 or earlier	34.6%

Bedrooms

Size	% of units
No bedroom (studio)	0.5%
1 bedroom	1.3%
2 bedrooms	17.9%
3 bedrooms	46.2%
4 bedrooms	24.8%
5+ bedrooms	9.3%

Vehicles per household

Vehicles	% of households
No vehicle	1.6%
1 vehicle	14.2%
2 vehicles	32.0%
3 or more	52.2%

Heating fuel

Fuel type	%
Utility gas	1.5%
Electricity	52.2%
Propane / LP gas	10.6%
Fuel oil	24.5%
Wood	9.0%
Solar	1.8%
No fuel used	0.4%

Households & families

Household type	Count	%
Married-couple family	614	58.6%
Cohabiting couple	39	3.7%
Male householder, no spouse	194	18.5%
Female householder, no spouse	201	19.2%
Households with children under 18	220	21.0%
Households with seniors (65+)	412	39.3%
Average household size	2.57

Marital status

Status	Male	Female
Never married	27.5%	29.4%
Married	57.6%	57.0%
Separated	2.6%	2.3%
Widowed	2.2%	7.3%
Divorced	10.0%	4.0%

Education

Less than 9th grade 5.7%

Some HS, no diploma 5.0%

HS graduate 37.2%

Some college, no degree 16.5%

Associate's degree 5.7%

Bachelor's degree 15.8%

Graduate / professional 14.0%

Metric	%
HS diploma or higher	89.3%
Bachelor's or higher	29.9%

School enrollment (ages 3–17)

Type	Count	%
Nursery / preschool	0	0.0%
Kindergarten	7	1.2%
Elementary school	323	56.2%
High school	69	12.0%
College / grad school	176	30.6%

Employment

Industry of employment

Education & healthcare 20.4%

Construction 17.4%

Professional & management 10.6%

Retail trade 9.9%

Agriculture & mining 7.8%

Manufacturing 7.3%

Public administration 6.7%

Transportation & utilities 5.4%

Other services 5.0%

Finance & real estate 4.8%

Arts, food & hospitality 3.7%

Wholesale trade 0.5%

Information 0.5%

Occupation

Category	%
Management, business & arts	37.0%
Service	10.1%
Sales & office	24.6%
Natural resources & construction	18.6%
Production & transportation	9.6%

Employment type

Type	%
Private sector	72.3%
Government	17.1%
Self-employed	8.4%
Unpaid family workers	2.2%

Commute

Method	%
Drive alone	73.1%
Carpool	6.6%
Public transit	0.0%
Walk	4.1%
Work from home	14.2%
Other means	2.0%
Avg commute (minutes)	35.5

Poverty

All people 2.7%

Under 18 years 0.0%

18 and over 3.3%

Married-couple families 1.0%

Female-led households 0.0%

Income support

Source	% of households
Social Security	39.1%
Retirement income	28.4%
Supplemental Security	0.9%
Cash public assistance	1.3%
Food stamps / SNAP	6.3%

Health indicators

Condition	%
Obesity	32.4%
High blood pressure	34.2%
High cholesterol	36.8%
Diabetes	10.2%
Heart disease	6.3%
Stroke	2.9%
Asthma	9.7%
Arthritis	26.0%
Kidney disease	2.8%
Pulmonary disease	6.9%
Cancer	7.2%

Behavior / access	%
Smoking	16.3%
Binge drinking	16.3%
No physical activity	21.7%
Less than 7 hrs sleep	30.1%
Depression	20.1%
Fair or poor health	12.5%
Poor mental health	14.3%
Poor physical health	9.3%
No health insurance	10.2%
Visited doctor (checkup)	76.0%
Visited dentist	65.6%
Cholesterol screening	91.7%
Teeth loss	11.4%

Veterans & disability

Veterans	Count	%
Civilian veterans	106	4.8%

Disability	%
Any disability	13.1%
Under 18	4.3%
18–64 years	11.3%
65 and over	26.3%

Health insurance coverage

Type	%
Private insurance	84.8%
Public insurance	32.6%
No insurance	2.2%
Uninsured under 19	0.0%

Language & origin

Language spoken at home (age 5+)

Language	Count	%
English only	2,571	94.5%
Spanish	47	1.8%
Other Indo-European	21	0.8%
Asian & Pacific Islander	26	1.0%
Other languages	0	0.0%

Place of birth & citizenship

Origin	Count	%
Native born (US)	2,631	96.7%
Born in same state	2,581	94.8%
Born in different state	1,637	60.1%
Foreign born	50	1.8%
Naturalized citizen	91	3.3%
Not a US citizen	74	81.3%

Ancestry

Ancestry	Count	%
Arab	384	14.1%
French	313	11.5%
Italian	204	7.5%

Ancestry	Count	%
Polish	22	0.8%
English	7	0.3%

Technology access

Metric	% of households
Computer access	38.5%
Internet access	93.4%

Source: U.S. Census Bureau, American Community Survey 2025 estimates.

Frequently asked questions about ZIP code 21757

What city is ZIP code 21757 in?

ZIP code 21757 is primarily assigned to Keymar, Maryland.

What county is ZIP code 21757 in?

ZIP code 21757 falls within Frederick County, Maryland.

Does ZIP code 21757 have a large retiree population?

39% of households in ZIP code 21757 receive Social Security income, suggesting a significant retiree or disability population.

What is the typical home value in ZIP code 21757?

The median home value in ZIP code 21757 is $425,000.

What is the population of ZIP code 21757?

ZIP code 21757 has an estimated population of 2,722 residents, with a density of 77 people per square mile.

What is the median household income in ZIP code 21757?

The median household income in ZIP code 21757 is $96,250, above the national median of ~$75,000.

What timezone is ZIP code 21757 in?

ZIP code 21757 observes the EST timezone.