21104 ZIP Code: Living in Marriottsville, MD

Updated November 2026 · Data: U.S. Census Bureau, American Community Survey 2020–2024

ZIP code 21104 is mostly in Howard County, with part in Carroll County and Baltimore County, Maryland, and covers Marriottsville. Spanning Howard, Carroll and Baltimore counties along the Patapsco River, with rural lots and newer subdivisions near Patapsco Valley State Park. About 6,052 people live in the 21104 ZIP code area.

21104 at a glance

Figures are Census estimates for ZIP Code Tabulation Area 21104, which closely follows the postal ZIP code. Estimates for smaller areas have wider margins of error.

Neighborhoods and communities in 21104

The 21104 ZIP code includes Marriottsville. ZIP code lines don’t always match neighborhood or school boundaries, so confirm the details for any specific address.

Homes in 21104: what the housing looks like

Housing in 21104 is mostly single-family detached homes. About 42% of homes were built in 2000 or later, so newer construction is common. About 97% of occupied homes are lived in by their owners, which is higher than the Maryland average of about 67%.

Type of home	Share of homes in 21104
Single-family detached	89%
Townhomes and rowhomes (attached)	8%
2–4 unit buildings	0%
Buildings with 5+ units (apartments, condos)	3%

Share of all housing units, ACS 2020–2024. 2,204 housing units in total.

Commuting from 21104

Workers living in 21104 average a 31.9-minute commute. About 21.1% work from home. Here is how far the center of the 21104 ZIP code is from major job centers and travel hubs. These are straight-line distances; drive times depend on route and traffic.

Destination	Distance
Downtown Baltimore	17 miles
Washington, D.C.	32 miles
BWI Airport	18 miles
Annapolis	34 miles
Fort Meade	19 miles
Columbia Town Center	10 miles
Towson	17 miles

Living in Howard County: what to know

Howard County has no incorporated cities; Columbia and Ellicott City are unincorporated communities governed by the county. Homes in the western part of the county often use well and septic rather than public water and sewer, so check that before you buy.

Public schools in 21104 are run by Howard County Public School System. Assignments go by street address, not ZIP code, so use the district’s school locator for a specific home. To compare schools, see the Maryland State Department of Education Report Card.

For taxes, commuting and lifestyle across the county, read our Howard County relocation guide. For parks and trails, see Howard County parks.

ZIP codes near 21104

• 21163 – Woodstock
• 21794 – West Friendship
• 21042 – Ellicott City
• 21723 – Cooksville
• 21133 – Randallstown
• 21244 – Windsor Mill

21104 ZIP code: frequently asked questions

What county is ZIP code 21104 in?

ZIP code 21104 is mostly in Howard County, Maryland, with part in Carroll County and Baltimore County.

What neighborhoods are in the 21104 ZIP code?

The 21104 ZIP code includes Marriottsville.

What is the median home value in 21104?

The median value of owner-occupied homes in 21104 is about $680,200, according to Census American Community Survey estimates for 2020–2024. Current asking prices can differ, so check active listings for today’s market.

How far is 21104 from Baltimore and Washington, D.C.?

The center of the 21104 ZIP code is about 17 miles from downtown Baltimore and 32 miles from Washington, D.C., in a straight line. Drive times vary with traffic.

Where can I see homes for sale in 21104?

You can see all current homes for sale in 21104 on GreatestMoves.com, our home search site, at https://www.greatestmoves.com/zip-codes/21104/.

Sources: U.S. Census Bureau, American Community Survey 5-year estimates 2020–2024 (tables DP03, DP04, DP05) for ZCTA 21104; U.S. Census Bureau TIGERweb ZCTA boundaries. Distances are calculated from the ZCTA’s internal point.