Residential delivery area · Maryland
ZIP Code 21057: Glen Arm, MD
ZIP code 21057 uses the postal name Glen Arm, Maryland and lies entirely in Baltimore County (Census 2020 ZIP-county file). About 4,400 people live there (Census Bureau, ACS 2020-2024). Median household income is $145,924 (Census Bureau, ACS 2020-2024). Its land lies outside any incorporated or census-designated place.
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Glen Arm · its only residential ZIP
- County
- Baltimore County
- Metro area
- Baltimore-Columbia-Towson, MD
- House district
- MD-1 119th Congress
- State
- Maryland
- Time zone
- Eastern
- Land area
- 15.9 sq mi · 276 people per sq mi
Where is ZIP code 21057?
21057 centers on 39.449°, -76.512° and covers 15.9 square miles of land plus 0.4 of water. It borders 6 ZIP codes: 21082, 21234, 21286, 21013, 21087, 21131.
The map draws ZIP code areas only. For the streets inside 21057, open its center on OpenStreetMap.
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries and the 2023 Gazetteer (2020 ZCTAs); ZIP-to-county shares, Census places and House districts (119th Congress) from the Census 2020 relationship files (shares of land); metro area from the OMB delineation (July 2023); town name and time zone from simplemaps US ZIP Codes (CC BY 4.0).
How does 21057 compare with the rest of Baltimore County?
| Measure | 21057 | In Baltimore County | In MD |
|---|---|---|---|
| People (ACS 2020-2024) | 4,386 | 44th of 57 | 249th of 477 |
| Median household income | $146k | not ranked | not ranked |
| Median home value | $623k | 3rd of 45 | 44th of 320 |
21057's median household income is not ranked: its 90% margin of error (±$40,333) is more than a quarter of the figure ($145,924). Rankings use ZIP codes of 1,000 or more people living in households, with margins at most 25% of the figure.
It is denser than 66% of U.S. residential ZIP codes. ZIP codes at the ACS caps ($250,000 or more for household income, $2,000,000 or more for home value) share the top rank.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B19013, B25077); ranks by PlainZIP over residential ZIP codes (ZCTAs).
How many people live in 21057?
The 2020 Census counted 4,060 people in 21057; the ACS, which samples households over 2020-2024, estimates 4,386. Between the 2010 and 2020 censuses its population fell 1.3% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 4,386±828 (90% margin)
- 2020 Census count
- 4,060−1.3% since 2010 (4,112)
- Households
- 1,545
- Median age
- 41.3
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B01002, B11001); 2020 Census (DHC P1); 2010 Census (SF1 P1).
Who lives in 21057?
Of the 4,386 people the ACS estimates in 21057, 25.0% are under 18 and 21.8% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (83.7%).
- Under 1825.0%
- 18 to 6453.2%
- 65 and older21.8%
- White, not Hispanic83.7%
- Hispanic or Latino7.1%
- Black, not Hispanic4.6%
- Other or two or more3.1%
- Asian, not Hispanic1.5%
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01001 age by sex, B03002 Hispanic or Latino origin by race); shares of the estimated population, small ZIP codes carry wide margins.
What do households in 21057 earn?
Median household income is $145,924 (ACS 2020-2024). It is not measurably different from 2015-2019 ($161,042 in 2024 dollars): the change is within the surveys' margins of error.
- Median household income
- $145,924±$40,333
- Income per person
- $61,920
- Below the poverty line
- 3.1%
- Unemployed (of the labor force)
- 1.7%
- Adults 25+ with a bachelor's degree
- 54.0%
- Adjusted gross income per tax return, 2022
- $140,0212,100 returns; wages 61% of AGI (IRS)
Source: U.S. Census Bureau, ACS 2020-2024 and 2015-2019 5-year estimates (B19013, B19301, B17001, B23025, B15003; 2015-2019 dollars converted with the BLS CPI-U, 1.22699); IRS Statistics of Income, ZIP code data, tax year 2022 (adjusted gross income per return, filed under the address on the return).
What are homes worth in 21057?
FHFA's house price index for 21057, built from repeat sales and appraisals of the same homes, rose 49% from 2015 to 2025 and rose 33% from 2020 to 2025, and moved +4.8% in 2025.
- Median home value (owners' estimate)
- $623,200
- Median gross rent
- $1,746
- Homes owned by their occupants
- 85.1%
- Housing units
- 1,603
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B25077, B25064, B25003, B25001); FHFA House Price Index, annual five-digit ZIP, updated 2026-03-31.
What businesses are in 21057?
110 business establishments had a location in this ZIP code in 2023, 2 fewer than in 2018; the most are in construction (ZIP Code Business Patterns).
- Construction29
- Professional, scientific, and technical services14
- Other services (except public administration)12
- Administrative and support and waste management and remediation services8
- Retail trade7
- Wholesale trade6
Source: U.S. Census Bureau, ZIP Code Business Patterns 2023 and 2018 (establishments with paid employees, by the business's ZIP code).
Which ZIP codes are next to 21057?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 21082 | Hydes | 626 | $146k | 2.9 mi |
| 21234 | Parkville | 66,334 | $84k | 4.0 mi |
| 21286 | Towson | 21,853 | $94k | 4.1 mi |
| 21013 | Baldwin | 5,610 | $171k | 4.5 mi |
| 21087 | Kingsville | 5,537 | $129k | 5.3 mi |
| 21131 | Phoenix | 7,141 | $198k | 5.6 mi |
| 21051 | Fork | 172 | $233k | 3.4 mi (near) |
| 21236 | Nottingham | 39,514 | $95k | 4.5 mi (near) |
| 21128 | Perry Hall | 15,501 | $128k | 4.6 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.