ZIP Code 21791

21791 is one of Maryland's ZIP codes, delivering to addresses in Union Bridge, Carroll County.

City: Union Bridge
County: Carroll County
State: Maryland
Prefix: 217xx

Where this code sits

21791 is part of the 217xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Union Bridge.

Union Bridge Maryland ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 21791 delivers to without sharing its boundary.

ZIP codes nearest 21791

The ZIP codes whose reference points sit closest to 21791.
ZIP code	Distance	Delivers to
ZIP code 21776	4.7 mi	New Windsor, MD
ZIP code 21158	5.8 mi	Westminster, MD
ZIP code 21787	6.3 mi	Taneytown, MD
ZIP code 21792	7.8 mi	Unionville, MD
ZIP code 21757	8.0 mi	Keymar, MD
ZIP code 21157	8.1 mi	Westminster, MD
ZIP code 21759	8.5 mi	Ladiesburg, MD
ZIP code 21775	8.7 mi	New Midway, 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 21791, plotted from its record coordinates.

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

Scope ZIP code 21791. 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.