ZIP Code 21057

21057 is one of Maryland's ZIP codes, delivering to addresses in Glen Arm, Baltimore County.

City: Glen Arm
County: Baltimore County
State: Maryland
Prefix: 210xx

Where this code sits

21057 is part of the 210xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Glen Arm.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 21057 delivers to without sharing its boundary.

ZIP codes nearest 21057

The ZIP codes whose reference points sit closest to 21057.
ZIP code	Distance	Delivers to
ZIP code 21092	1.1 mi	Long Green, MD
ZIP code 21082	2.7 mi	Hydes, MD
ZIP code 21051	3.7 mi	Fork, MD
ZIP code 21131	3.8 mi	Phoenix, MD
ZIP code 21094	4.3 mi	Lutherville Timonium, MD
ZIP code 21251	4.3 mi	Baltimore, MD
ZIP code 21286	4.4 mi	Towson, MD
ZIP code 21013	4.4 mi	Baldwin, MD

Straight-line distance between place reference points, not driving distance. Where a place has no Census Gazetteer point, its postal centroid is used instead.

Each point is the reference point for 21057, plotted from its record coordinates.

Reference points and footprint
Not an official NANPA boundary
Not a USPS delivery area

Scope ZIP code 21057. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated 15 July 2026. A ZIP code is a set of delivery routes, not an area; the point shown is a record coordinate, not a centre.