ZIP Code 21023

21023 is one of Maryland's ZIP codes, delivering to addresses in Butler, Baltimore County.

City: Butler
County: Baltimore County
State: Maryland
Prefix: 210xx

Where this code sits

21023 is part of the 210xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Butler.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 21023 delivers to without sharing its boundary.

ZIP codes nearest 21023

The ZIP codes whose reference points sit closest to 21023.
ZIP code	Distance	Delivers to
ZIP code 21020	3.4 mi	Boring, MD
ZIP code 21152	3.4 mi	Sparks Glencoe, MD
ZIP code 21155	3.7 mi	Upperco, MD
ZIP code 21030	4.9 mi	Cockeysville, MD
ZIP code 21071	5.4 mi	Glyndon, MD
ZIP code 21065	5.7 mi	Hunt Valley, MD
ZIP code 21031	5.9 mi	Hunt Valley, MD
ZIP code 21136	6.3 mi	Reisterstown, 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 21023, plotted from its record coordinates.

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

Scope ZIP code 21023. 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.