ZIP Code 21010

21010 is one of Maryland's ZIP codes, delivering to addresses in Gunpowder, Harford County.

City: Gunpowder
County: Harford County
State: Maryland
Prefix: 210xx

Where this code sits

21010 is part of the 210xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Gunpowder.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 21010 delivers to without sharing its boundary.

ZIP codes nearest 21010

The ZIP codes whose reference points sit closest to 21010.
ZIP code	Distance	Delivers to
ZIP code 21040	2.6 mi	Edgewood, MD
ZIP code 21085	4.6 mi	Joppa, MD
ZIP code 21009	5.4 mi	Abingdon, MD
ZIP code 21017	5.6 mi	Belcamp, MD
ZIP code 21027	5.7 mi	Chase, MD
ZIP code 21130	6.1 mi	Perryman, MD
ZIP code 21156	7.1 mi	Upper Falls, MD
ZIP code 21162	7.4 mi	White Marsh, 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 21010, plotted from its record coordinates.

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

Scope ZIP code 21010. 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.