21778 ZIP Code — Rocky Ridge, MD

Frederick County, Maryland

ZIP code 21778 is located in Rocky Ridge, Maryland, within Frederick County. It covers approximately 18.24 square miles and serves a population of 880 residents. This is a standard ZIP code in the Eastern (ET) timezone, served by area code 240/301.

About ZIP code 21778

The housing stock consists of predominantly single-family detached homes. Most homes were built in the 1970s, giving the area an established character. Median home value is $373,100. Owner-occupancy is high at 92%, well above the national average.

The gap between median ($76,063) and mean household income suggests income inequality — a small number of higher earners pull the average up. The poverty rate of 4% is below the national average. 56% of households receive Social Security income, suggesting a notable retiree or disability population.

The dominant occupation class is management, business, and professional, with construction as the leading industry. The average commute of 29 minutes is near the national average.

College attainment at 18% is below the national average, consistent with a trades and production-oriented local economy.

Overall, ZIP code 21778 reflects a community defined by a trades-oriented workforce, high homeownership, and a significant Social Security-dependent population.

880

population

18.24

sq mi land

Standard

ZIP type

Eastern (ET)

timezone

21778 ZIP code map

Cities in ZIP code 21778

Below are the cities the US Postal Service accepts for ZIP code 21778. Using any city not on this list may result in mail delivery delays.

City	Status
Rocky Ridge	Preferred

Nearby ZIP codes

21727 Emmitsburg (4.4 mi) 21757 Keymar (4.7 mi) 21788 Thurmont (4.9 mi) 21798 Woodsboro (5.2 mi) 21793 Walkersville (8.2 mi) 21780 Sabillasville (8.4 mi) 21787 Taneytown (9 mi) 21791 Union Bridge (9.5 mi) 21701 Frederick (10.2 mi) 21702 Frederick (10.2 mi) 21719 Cascade (10.7 mi) 17214 Blue Ridge Summit (11.3 mi)

Demographics updated 05/2026

Population
Total population	880
Population density	48 / sq mi
State FIPS	24
County FIPS	021

Geography
Land area	18.24 sq mi
Water area	0.37 sq mi
Latitude	39.6118
Longitude	-77.3340
Timezone	Eastern (ET)
Area code	240/301

Total population by age

Gender

Race & ethnicity

Economics updated 05/2026

Household income

Income range	This ZIP	County avg	State avg
Under $50k	40.3%	22.0%	28.2%
$50k – $100k	34.1%	27.2%	28.2%
$100k – $200k	22.6%	36.5%	30.1%
Over $200k	3.1%	14.3%	13.4%

Demographics & statistics

880

Population

People per sq mi

54.6

Median age

$76,063

Median household income

$50,106

Per capita income

$373,100

Median home value

Median monthly rent

91.7%

Home ownership

4.3%

Poverty rate

4.1%

Unemployment

381

Housing units

17.7%

Bachelor's or higher

Age distribution

Male Female

Under 5

5–9

10–14

15–19

20–24

25–34

35–44

45–54

55–59

60–64

65–74

75–84

85+

← Male

Female →

Age summary

Group	Count	%
Under 18	93	10.6%
18 and over	787	89.4%
65 and over	302	34.3%
Median age	54.6 years

Race & ethnicity

White 100%

Group	Count	%
White	880	100%

Household income

Income range	This ZIP	County avg	State avg
Under $50k	40.3%	22.0%	28.2%
$50k – $100k	34.1%	27.2%	28.2%
$100k – $200k	22.6%	36.5%	30.1%
Over $200k	3.1%	14.3%	13.4%

Under $10k 2.7%

$15k–$25k 10.7%

$25k–$35k 1.6%

$35k–$50k 2.1%

$50k–$75k 30.6%

$75k–$100k 7.2%

$100k–$150k 14.5%

$150k–$200k 15.5%

$200k+ 15.0%

Range	% of households
Under $10k	2.7%
$15k–$25k	10.7%
$25k–$35k	1.6%
$35k–$50k	2.1%
$50k–$75k	30.6%
$75k–$100k	7.2%
$100k–$150k	14.5%
$150k–$200k	15.5%
$200k+	15.0%
Median income	$76,063

Housing

Home values

$100k–$150k 1.8%

$200k–$300k 42.7%

$300k–$500k 21.1%

$500k–$1M 30.1%

$1M+ 4.4%

Housing overview

Metric	Value
Median home value	$373,100
Median rent / month	$0
Owner occupied	91.7%
Renter occupied	8.3%
Vacant	9.5%
Single-family detached	88.1%
Large apartment buildings	1.7%
Mobile homes	3.4%
Median rooms	6.5
Avg household size (owned)	2.38

Year built

Era	%
2020 or later	0.0%
2010–2019	0.0%
2000–2009	8.5%
1990–1999	3.2%
1980–1989	5.6%
1970–1979	30.3%
1960–1969	16.3%
1950–1959	2.7%
1940–1949	3.6%
1939 or earlier	29.9%

Bedrooms

Size	% of units
No bedroom (studio)	1.7%
1 bedroom	0.0%
2 bedrooms	7.3%
3 bedrooms	68.9%
4 bedrooms	15.0%
5+ bedrooms	7.0%

Vehicles per household

Vehicles	% of households
No vehicle	12.6%
1 vehicle	11.3%
2 vehicles	37.8%
3 or more	38.3%

Heating fuel

Fuel type	%
Utility gas	9.7%
Electricity	41.0%
Propane / LP gas	12.1%
Fuel oil	21.7%
Wood	15.5%

Households & families

Household type	Count	%
Married-couple family	176	47.2%
Cohabiting couple	20	5.4%
Male householder, no spouse	11	2.9%
Female householder, no spouse	166	44.5%
Households with children under 18	56	15.0%
Households with seniors (65+)	225	60.3%
Average household size	2.36

Marital status

Status	Male	Female
Never married	36.5%	16.9%
Married	50.4%	39.3%
Separated	0.0%	0.0%
Widowed	0.0%	26.7%
Divorced	13.1%	17.1%

Education

Less than 9th grade 4.5%

Some HS, no diploma 5.4%

HS graduate 40.9%

Some college, no degree 18.0%

Associate's degree 13.6%

Bachelor's degree 5.7%

Graduate / professional 12.0%

Metric	%
HS diploma or higher	90.1%
Bachelor's or higher	17.7%

School enrollment (ages 3–17)

Type	Count	%
Nursery / preschool	0	0.0%
Kindergarten	0	0.0%
Elementary school	30	24.4%
High school	50	40.7%
College / grad school	43	35.0%

Employment

Industry of employment

Construction 32.1%

Education & healthcare 15.4%

Public administration 15.2%

Retail trade 12.4%

Agriculture & mining 7.7%

Professional & management 5.2%

Arts, food & hospitality 3.5%

Manufacturing 2.5%

Finance & real estate 2.2%

Transportation & utilities 2.0%

Other services 1.7%

Occupation

Category	%
Management, business & arts	34.6%
Service	10.7%
Sales & office	26.4%
Natural resources & construction	20.6%
Production & transportation	7.7%

Employment type

Type	%
Private sector	68.9%
Government	18.7%
Self-employed	12.4%
Unpaid family workers	0.0%

Commute

Method	%
Drive alone	70.9%
Carpool	15.0%
Public transit	0.0%
Walk	1.9%
Work from home	12.3%
Other means	0.0%
Avg commute (minutes)	28.5

Poverty

All people 4.3%

Under 18 years 9.7%

18 and over 3.7%

Married-couple families 5.7%

Female-led households 0.0%

Income support

Source	% of households
Social Security	55.8%
Retirement income	36.7%
Supplemental Security	1.6%
Cash public assistance	1.6%
Food stamps / SNAP	4.3%

Health indicators

Condition	%
Obesity	33.4%
High blood pressure	34.4%
High cholesterol	38.6%
Diabetes	10.9%
Heart disease	6.5%
Stroke	3.0%
Asthma	10.2%
Arthritis	26.2%
Kidney disease	2.8%
Pulmonary disease	7.3%
Cancer	7.3%

Behavior / access	%
Smoking	16.4%
Binge drinking	16.2%
No physical activity	22.8%
Less than 7 hrs sleep	31.9%
Depression	21.5%
Fair or poor health	13.0%
Poor mental health	14.8%
Poor physical health	9.6%
No health insurance	10.8%
Visited doctor (checkup)	75.3%
Visited dentist	64.9%
Cholesterol screening	91.5%
Teeth loss	11.7%

Veterans & disability

Veterans	Count	%
Civilian veterans	71	9.0%

Disability	%
Any disability	20.5%
Under 18	0.0%
18–64 years	11.3%
65 and over	41.4%

Health insurance coverage

Type	%
Private insurance	75.9%
Public insurance	35.1%
No insurance	5.2%
Uninsured under 19	8.0%

Language & origin

Language spoken at home (age 5+)

Language	Count	%
English only	842	95.7%
Spanish	0	0.0%
Other Indo-European	0	0.0%
Asian & Pacific Islander	0	0.0%
Other languages	0	0.0%

Place of birth & citizenship

Origin	Count	%
Native born (US)	873	99.2%
Born in same state	873	99.2%
Born in different state	604	68.6%
Foreign born	0	0.0%
Naturalized citizen	7	0.8%
Not a US citizen	0	0.0%

Ancestry

Ancestry	Count	%
Arab	96	10.9%
French	53	6%
Norwegian	27	3.1%

Ancestry	Count	%
English	22	2.5%
Polish	20	2.3%
Italian	7	0.8%

Technology access

Metric	% of households
Computer access	42.4%
Internet access	70.2%

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

Frequently asked questions about ZIP code 21778

What city is ZIP code 21778 in?

ZIP code 21778 is primarily assigned to Rocky Ridge, Maryland.

What county is ZIP code 21778 in?

ZIP code 21778 falls within Frederick County, Maryland.

Does ZIP code 21778 have an older population?

34% of residents in ZIP code 21778 are 65 or older, above the national average of ~17%.

Does ZIP code 21778 have a large retiree population?

56% of households in ZIP code 21778 receive Social Security income, suggesting a significant retiree or disability population.

Is ZIP code 21778 mostly owner-occupied?

92% of occupied units in ZIP code 21778 are owner-occupied, well above the national average.

What is the typical home value in ZIP code 21778?

The median home value in ZIP code 21778 is $373,100.

What timezone is ZIP code 21778 in?

ZIP code 21778 observes the EST timezone.