ZIP Code 21104
standardSource:
Marriottsville · Carroll County · Maryland
- Population
- 4,601
- Median income
- $191,804
- Median home value
- $680,200
- Bachelor's or higher
- 64.4%
- Land area
- 44.0 sq mi
105/sq mi
▲ 151% vs US
higher than 99% of US ZIPs
▲ 145% vs US
higher than 93% of US ZIPs
Median age 43.1
New York
ZIP code 21104 in Marriottsville, Maryland has a population of 4,601. The median household income is $191,804, which is 151% above the national average. Median home value is $680,200, 145% above the US average. 64.4% of residents hold a bachelor's degree or higher.
ZIP code 21104 is classified by USPS as a standard delivery area and covers roughly 44.0 square miles in Marriottsville, Carroll County, Maryland. The area is home to 4,601 residents, producing a population density of 105 people per square mile, and falls within the New York time zone. These USPS and Census boundary values drive every downstream statistic on this page, including the benchmarks that compare 21104 against Maryland and the nation.
On the economic side, the median household income for ZIP 21104 sits at $191,804 (68% above the Maryland average), while per-capita income is $74,405. The poverty rate stands at 2.7% and the unemployment rate at 3.2%. On housing, the median home value is $680,200 (52% above the state average) with median rent at $1,384 per month, and 97.0% of occupied units are owner-occupied, a direct signal of whether 21104 behaves more like a homeowner neighborhood or a renter-heavy ZIP.
Education and household profile round out the picture: 64.4% of adults hold a bachelor's degree or higher, the median age is 43.1, and the average commute is 32 minutes. We also surface 10 nearby ZIP codes within roughly 10 miles and 6 additional ZIPs sharing Carroll County, so you can benchmark 21104 against its immediate geography rather than a national average alone. Every figure is sourced from the U.S. Census Bureau American Community Survey 5-Year Estimates, HUD Fair Market Rents, and FHFA Home Price Index data, no estimates, no proprietary scoring. Verify with HUD →
Top industries in ZIP 21104
Top 5 sectors by establishment count
Which industries have the most business establishments in ZIP 21104.
- Professional, scientific, and technical services
Professional, scientific, and technical services
40 establishments
- Construction
Construction
20 establishments
- Health care and social assistance
Health care and social assistance
16 establishments
- Finance and insurance 11
Finance and insurance
11 establishments
- Administrative and support and waste management and remediation services 11
Administrative and support and waste management and remediation services
11 establishments
What this shows Establishment counts come from the Census ZIP Code Business Patterns program, which counts physical business locations rather than employees or revenue.
Source: U.S. Census Bureau, American Community Survey 5-Year Estimates + ZIP Code Business Patterns + HUD FMR + FHFA HPI ACS demographics, ZBP business establishments, HUD Fair Market Rents, FHFA HPI for ZIP 21104, Marriottsville, MD · 2023 Census ACS 5-Year Estimates use a rolling 60-month sample for stable small-geography estimates; ZBP updated annually; HUD FMR + FHFA HPI updated quarterly/annually.
Quick Facts
4,601
Population
44.0
Area (sq mi)
105
People / sq mi
New York
Time Zone
standard
ZIP Type
Who lives in ZIP 21104?
43.1
Median Age
50.0%
Male
50.0%
Female
16.0%
Foreign-Born
Hispanic or Latino is an ethnicity category from the Census Bureau and may overlap with other categories above.
Source: U.S. Census Bureau, ACS 5-Year Estimates (2023)
How much do residents earn?
$191,804
Median Household Income
+68% vs state
$74,405
Per Capita Income
2.7%
Poverty Rate
3.2%
Unemployment Rate
31.9 min
Mean Commute Time
Source: U.S. Census Bureau, ACS 5-Year Estimates (2023)
What is the education profile here?
Source: U.S. Census Bureau, ACS 5-Year Estimates (2023)
What does housing look like?
2,204
Total Housing Units
2,097
Occupied Units
107
Vacant Units
2.88
Avg Household Size
Occupancy Type
$680,200
Median Home Value
+52% vs state
$1,384
Median Rent
1995
Median Year Built
Source: U.S. Census Bureau, ACS 5-Year Estimates (2023)
How have home values changed over time?
FHFA House Price Index, annual appreciation data based on repeat sales and appraisals
-3.1%
YoY Change (2024)
252
HPI Index (2000 = 100)
+152%
Total Change Since 2000
Home values in ZIP 21104 have decreased 3.1% over the past year (2024). Since 2000, this ZIP has seen +152% cumulative appreciation.
| Year | Annual Change | HPI Index |
|---|---|---|
| 2020 | +5.5% | 188 |
| 2021 | +8.3% | 203 |
| 2022 | +13.9% | 232 |
| 2023 | +12.1% | 260 |
| 2024 | -3.1% | 252 |
Source: Federal Housing Finance Agency (FHFA) House Price Index, All-Transactions, Five-Digit ZIP Codes (Developmental Index). Index base = 100 in year 2000. Data through 2024. ZIP codes with few transactions may show missing values.
What businesses operate in this ZIP?
Census Bureau data shows 157 business establishments in ZIP 21104, employing approximately 1,322 people with a combined annual payroll of $72,588,000.
157
Businesses
1,322
Employees
$72.6M
Annual Payroll
12
Industry Sectors
| Industry | Establishments | % of Total |
|---|---|---|
| Professional, scientific, and technical services | 40 | 25.5% |
| Construction | 20 | 12.7% |
| Health care and social assistance | 16 | 10.2% |
| Finance and insurance | 11 | 7.0% |
| Administrative and support and waste management and remediation services | 11 | 7.0% |
| Other services (except public administration) | 11 | 7.0% |
| Real estate and rental and leasing | 10 | 6.4% |
| Wholesale trade | 9 | 5.7% |
| Accommodation and food services | 9 | 5.7% |
| Arts, entertainment, and recreation | 6 | 3.8% |
| Retail trade | 4 | 2.5% |
| Transportation and warehousing | 3 | 1.9% |
Source: U.S. Census Bureau, ZIP Code Business Patterns (ZBP), 2023. Employment figures may include noise for disclosure avoidance.
Nearby ZIP Codes
Want a side-by-side? Compare 21104 vs 21163 →
| ZIP Code | City | Population | Distance |
|---|---|---|---|
| 21163 | Woodstock, MD | 7,026 | 2.8 mi |
| 21042 | Ellicott City, MD | 38,076 | 5.5 mi |
| 21784 | Sykesville, MD | 37,941 | 5.0 mi |
| 21794 | West Friendship, MD | 2,434 | 5.1 mi |
| 21133 | Randallstown, MD | 29,998 | 5.3 mi |
| 21723 | Cooksville, MD | 803 | 5.8 mi |
| 21244 | Windsor Mill, MD | 34,611 | 6.8 mi |
| 21048 | Finksburg, MD | 10,650 | 10.1 mi |
| 21044 | Columbia, MD | 41,704 | 9.7 mi |
| 21738 | Glenwood, MD | 3,268 | 8.0 mi |
More ZIP Codes in Carroll County
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Frequently Asked Questions
What county is ZIP code 21104 in? ▼
What is the population of ZIP code 21104? ▼
What is the median household income in ZIP 21104? ▼
What is the average home value in ZIP 21104? ▼
What is the demographic makeup of ZIP 21104? ▼
How many businesses are in ZIP code 21104? ▼
What are the main industries in ZIP code 21104? ▼
How have home values changed in ZIP code 21104? ▼
What is the education level in ZIP code 21104? ▼
What is the average commute time in ZIP 21104? ▼
What percentage of residents own vs. rent in ZIP 21104? ▼
What is the poverty rate in ZIP code 21104? ▼
ZIP Code Research Guides
Official Data Resources for Marriottsville, MD
Verify and explore additional data for this area using these official government sources.
Source: U.S. Census Bureau, ACS 5-Year Estimates (2023). Business data: Source: Census ZIP Code Business Patterns (ZBP) 2023. Home value trends: Source: FHFA House Price Index (HPI), Five-Digit ZIP Codes.
PlainZIP is not affiliated with the U.S. Census Bureau or any government agency.
Read our methodology , how this data is sourced, computed, and verified.