21057 ZIP Code: Living in Glen Arm, MD
Updated November 2026 · Data: U.S. Census Bureau, American Community Survey 2020–2024
ZIP code 21057 is in Baltimore County, Maryland, and covers Glen Arm and Long Green (part). Rolling countryside east of Towson and Loch Raven Reservoir, with larger lots, horse farms and the Gunpowder area nearby. About 4,386 people live in the 21057 ZIP code area.
21057 at a glance
Figures are Census estimates for ZIP Code Tabulation Area 21057, which closely follows the postal ZIP code. Estimates for smaller areas have wider margins of error.
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Neighborhoods and communities in 21057
The 21057 ZIP code includes Glen Arm and Long Green (part). ZIP code lines don’t always match neighborhood or school boundaries, so confirm the details for any specific address.
Homes in 21057: what the housing looks like
Housing in 21057 is mostly single-family detached homes. Most homes were built before 2000; about 7% date from 2000 or later. About 85% 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 21057 |
|---|---|
| Single-family detached | 87% |
| Townhomes and rowhomes (attached) | 4% |
| 2–4 unit buildings | 1% |
| Buildings with 5+ units (apartments, condos) | 8% |
Share of all housing units, ACS 2020–2024. 1,603 housing units in total.
Commuting from 21057
Workers living in 21057 average a 32.7-minute commute. About 23.2% work from home. Here is how far the center of the 21057 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 | 12 miles |
| Washington, D.C. | 47 miles |
| BWI Airport | 21 miles |
| Annapolis | 33 miles |
| Fort Meade | 27 miles |
| Columbia Town Center | 25 miles |
| Towson | 6 miles |
Living in Baltimore County: what to know
Baltimore County has no incorporated cities, so communities such as this one are governed by the county. Property taxes, schools, police and trash service all run through Baltimore County government.
Public schools in 21057 are run by Baltimore County Public Schools. 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 Baltimore County relocation guide. For parks and trails, see Baltimore County parks.
ZIP codes near 21057
Looking at homes in 21057?
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21057 ZIP code: frequently asked questions
What county is ZIP code 21057 in?
ZIP code 21057 is in Baltimore County, Maryland.
What neighborhoods are in the 21057 ZIP code?
The 21057 ZIP code includes Glen Arm and Long Green (part).
What is the median home value in 21057?
The median value of owner-occupied homes in 21057 is about $623,200, 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 21057 from Baltimore and Washington, D.C.?
The center of the 21057 ZIP code is about 12 miles from downtown Baltimore and 47 miles from Washington, D.C., in a straight line. Drive times vary with traffic.
Where can I see homes for sale in 21057?
You can see all current homes for sale in 21057 on GreatestMoves.com, our home search site, at https://www.greatestmoves.com/zip-codes/21057/.
Sources: U.S. Census Bureau, American Community Survey 5-year estimates 2020–2024 (tables DP03, DP04, DP05) for ZCTA 21057; U.S. Census Bureau TIGERweb ZCTA boundaries. Distances are calculated from the ZCTA’s internal point.