21104 ZIP Code — Marriottsville, MD

Carroll County, Maryland

ZIP code 21104 is located in Marriottsville, Maryland, within Carroll County. It covers approximately 17.05 square miles and serves a population of 6,077 residents. This is a standard ZIP code in the Eastern (ET) timezone, served by area code 443/410.

About ZIP code 21104

The housing stock consists of predominantly single-family detached homes. Most homes were built in the 1990s, giving the area an established character. Median home value is $659,400. Owner-occupancy is high at 95%, well above the national average.

Median household income is $195,000. The poverty rate of 2% is below the national average. 31% 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. The average commute of 32 minutes is near the national average.

Educational attainment is high — 57% of residents hold a bachelor's degree or higher, well above the national average of 33%.

Overall, ZIP code 21104 reflects a community defined by a highly educated population, high homeownership, and a significant Social Security-dependent population.

6,077

population

17.05

sq mi land

Standard

ZIP type

Eastern (ET)

timezone

21104 ZIP code map

Cities in ZIP code 21104

Below are the cities the US Postal Service accepts for ZIP code 21104. Using any city not on this list may result in mail delivery delays.

City	Status
Marriottsville	Acceptable
Marriottsville	Preferred

Nearby ZIP codes

21163 Woodstock (2.5 mi) 21042 Ellicott City (4.6 mi) 21784 Sykesville (4.8 mi) 21794 West Friendship (5 mi) 21133 Randallstown (5.3 mi) 21244 Windsor Mill (6.5 mi) 21738 Glenwood (7.8 mi) 21737 Glenelg (8.3 mi) 21117 Owings Mills (8.5 mi) 21043 Ellicott City (8.5 mi) 21036 Dayton (9.2 mi) 21797 Woodbine (9.3 mi)

Demographics updated 05/2026

Population
Total population	6,077
Population density	356 / sq mi
State FIPS	24
County FIPS	013

Geography
Land area	17.05 sq mi
Water area	0.81 sq mi
Latitude	39.3429
Longitude	-76.9048
Timezone	Eastern (ET)
Area code	443/410

Total population by age

Gender

Race & ethnicity

Economics updated 05/2026

Household income

Income range	This ZIP	County avg	State avg
Under $50k	12.8%	23.8%	28.2%
$50k – $100k	11.1%	26.3%	28.2%
$100k – $200k	37.7%	37.1%	30.1%
Over $200k	38.4%	12.8%	13.4%

Demographics & statistics

6,077

Population

356

People per sq mi

46.1

Median age

$195,000

Median household income

$70,089

Per capita income

$659,400

Median home value

Median monthly rent

95.0%

Home ownership

2.3%

Poverty rate

1.5%

Unemployment

1,971

Housing units

57.4%

Bachelor's or higher

Age distribution

Male Female

138

Under 5

141

151

5–9

154

230

10–14

234

181

15–19

184

237

20–24

242

222

25–34

227

328

35–44

335

395

45–54

403

309

55–59

315

243

60–64

247

369

65–74

375

158

75–84

160

85+

← Male

Female →

Age summary

Group	Count	%
Under 18	1,304	21.5%
18 and over	4,773	78.5%
65 and over	1,161	19.1%
Median age	46.1 years

Race & ethnicity

White 74.4%

Asian 10.3%

Two or more races 5.5%

Black or African American 5.3%

Hispanic or Latino 3.9%

Other race 0.6%

Group	Count	%
White	4,707	74.4%
Asian	650	10.3%
Two or more races	345	5.5%
Black or African American	335	5.3%
Hispanic or Latino	249	3.9%
Other race	40	0.6%

Household income

Income range	This ZIP	County avg	State avg
Under $50k	12.8%	23.8%	28.2%
$50k – $100k	11.1%	26.3%	28.2%
$100k – $200k	37.7%	37.1%	30.1%
Over $200k	38.4%	12.8%	13.4%

Under $10k 0.8%

$10k–$15k 3.1%

$15k–$25k 1.1%

$25k–$35k 1.7%

$35k–$50k 4.4%

$50k–$75k 6.5%

$75k–$100k 5.2%

$100k–$150k 16.8%

$150k–$200k 14.1%

$200k+ 46.3%

Range	% of households
Under $10k	0.8%
$10k–$15k	3.1%
$15k–$25k	1.1%
$25k–$35k	1.7%
$35k–$50k	4.4%
$50k–$75k	6.5%
$75k–$100k	5.2%
$100k–$150k	16.8%
$150k–$200k	14.1%
$200k+	46.3%
Median income	$195,000

Housing

Home values

$100k–$150k 1.2%

$200k–$300k 0.8%

$300k–$500k 18.9%

$500k–$1M 74.5%

$1M+ 4.5%

Housing overview

Metric	Value
Median home value	$659,400
Median rent / month	$0
Owner occupied	95.0%
Renter occupied	5.0%
Vacant	2.3%
Single-family detached	87.6%
Large apartment buildings	0.0%
Mobile homes	0.0%
Median rooms	8.3
Avg household size (owned)	3.05

Year built

Era	%
2020 or later	0.9%
2010–2019	20.3%
2000–2009	17.6%
1990–1999	21.0%
1980–1989	16.3%
1970–1979	16.9%
1960–1969	2.5%
1950–1959	2.1%
1940–1949	0.3%
1939 or earlier	2.2%

Bedrooms

Size	% of units
No bedroom (studio)	0.0%
1 bedroom	0.0%
2 bedrooms	4.8%
3 bedrooms	36.0%
4 bedrooms	42.6%
5+ bedrooms	16.5%

Vehicles per household

Vehicles	% of households
No vehicle	0.6%
1 vehicle	13.6%
2 vehicles	40.1%
3 or more	45.6%

Heating fuel

Fuel type	%
Utility gas	34.9%
Electricity	37.9%
Propane / LP gas	7.3%
Fuel oil	12.2%
Wood	4.0%
No fuel used	3.1%

Households & families

Household type	Count	%
Married-couple family	1,442	71.2%
Cohabiting couple	85	4.2%
Male householder, no spouse	60	3.0%
Female householder, no spouse	439	21.7%
Households with children under 18	704	34.7%
Households with seniors (65+)	774	38.2%
Average household size	2.98

Marital status

Status	Male	Female
Never married	24.8%	24.3%
Married	65.7%	56.4%
Separated	0.0%	0.2%
Widowed	0.8%	10.4%
Divorced	8.8%	8.7%

Education

Less than 9th grade 2.5%

Some HS, no diploma 0.4%

HS graduate 19.7%

Some college, no degree 16.6%

Associate's degree 3.5%

Bachelor's degree 36.4%

Graduate / professional 21.0%

Metric	%
HS diploma or higher	97.1%
Bachelor's or higher	57.4%

School enrollment (ages 3–17)

Type	Count	%
Nursery / preschool	124	8.3%
Kindergarten	36	2.4%
Elementary school	631	42.1%
High school	329	22.0%
College / grad school	378	25.2%

Employment

Industry of employment

Education & healthcare 27.7%

Professional & management 17.3%

Finance & real estate 9.8%

Arts, food & hospitality 8.9%

Public administration 7.9%

Manufacturing 6.3%

Retail trade 5.0%

Construction 4.3%

Transportation & utilities 4.3%

Other services 3.8%

Wholesale trade 2.9%

Information 1.8%

Occupation

Category	%
Management, business & arts	64.2%
Service	10.1%
Sales & office	15.3%
Natural resources & construction	5.4%
Production & transportation	5.0%

Employment type

Type	%
Private sector	78.1%
Government	17.8%
Self-employed	3.9%
Unpaid family workers	0.3%

Commute

Method	%
Drive alone	79.2%
Carpool	3.3%
Public transit	0.3%
Walk	0.3%
Work from home	16.9%
Other means	0.0%
Avg commute (minutes)	31.5

Poverty

All people 2.3%

Under 18 years 0.5%

18 and over 2.8%

Married-couple families 0.6%

Female-led households 8.1%

Income support

Source	% of households
Social Security	30.8%
Retirement income	27.6%
Supplemental Security	2.2%
Cash public assistance	0.3%
Food stamps / SNAP	0.7%

Health indicators

Condition	%
Obesity	27.9%
High blood pressure	30.1%
High cholesterol	34.5%
Diabetes	7.8%
Heart disease	4.4%
Stroke	2.1%
Asthma	8.7%
Arthritis	21.9%
Kidney disease	2.1%
Pulmonary disease	4.3%
Cancer	6.6%

Behavior / access	%
Smoking	11.0%
Binge drinking	15.4%
No physical activity	15.6%
Less than 7 hrs sleep	28.3%
Depression	17.2%
Fair or poor health	8.2%
Poor mental health	11.9%
Poor physical health	6.8%
No health insurance	6.6%
Visited doctor (checkup)	76.5%
Visited dentist	74.8%
Cholesterol screening	94.0%
Teeth loss	6.1%

Veterans & disability

Veterans	Count	%
Civilian veterans	295	6.2%

Disability	%
Any disability	7.2%
Under 18	4.3%
18–64 years	5.7%
65 and over	15.4%

Health insurance coverage

Type	%
Private insurance	90.6%
Public insurance	24.0%
No insurance	3.4%
Uninsured under 19	0.0%

Language & origin

Language spoken at home (age 5+)

Language	Count	%
English only	5,798	95.4%
Spanish	251	4.3%
Other Indo-European	0	0.0%
Asian & Pacific Islander	25	0.4%
Other languages	226	3.9%

Place of birth & citizenship

Origin	Count	%
Native born (US)	5,308	87.3%
Born in same state	5,203	85.6%
Born in different state	3,399	55.9%
Foreign born	105	1.7%
Naturalized citizen	769	12.7%
Not a US citizen	645	83.9%

Ancestry

Ancestry	Count	%
Italian	1,176	19.4%
French	517	8.5%
Arab	189	3.1%
Norwegian	71	1.2%

Ancestry	Count	%
Polish	49	0.8%
English	31	0.5%
Irish	17	0.3%
Dutch	14	0.2%

Technology access

Metric	% of households
Computer access	33.3%
Internet access	96.7%

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

Frequently asked questions about ZIP code 21104

What city is ZIP code 21104 in?

ZIP code 21104 is primarily assigned to Marriottsville, Maryland.

What county is ZIP code 21104 in?

ZIP code 21104 falls within Howard County, Maryland.

Is ZIP code 21104 mostly owner-occupied?

95% of occupied units in ZIP code 21104 are owner-occupied, well above the national average.

How educated is the population of ZIP code 21104?

57% of residents hold a bachelor's degree or higher — well above the national average of ~33%, reflecting a highly educated population.

What is the median household income in ZIP code 21104?

The median household income in ZIP code 21104 is $195,000, above the national median of ~$75,000.

What is the typical home value in ZIP code 21104?

The median home value in ZIP code 21104 is $659,400.

What timezone is ZIP code 21104 in?

ZIP code 21104 observes the EST timezone.