ZIP Code 21918

21918 is one of Maryland's ZIP codes, delivering to addresses in Conowingo, Cecil County.

City: Conowingo
County: Cecil County
State: Maryland
Prefix: 219xx

Where this code sits

21918 is part of the 219xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Conowingo.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 21918 delivers to without sharing its boundary.

ZIP codes nearest 21918

The ZIP codes whose reference points sit closest to 21918.
ZIP code	Distance	Delivers to
ZIP code 21917	3.4 mi	Colora, MD
ZIP code 21034	4.1 mi	Darlington, MD
ZIP code 21911	5.8 mi	Rising Sun, MD
ZIP code 17563	6.5 mi	Peach Bottom, PA
ZIP code 21904	6.6 mi	Port Deposit, MD
ZIP code 19362	7.9 mi	Nottingham, PA
ZIP code 21160	8.7 mi	Whiteford, MD
ZIP code 21078	8.9 mi	Havre De Grace, 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 21918, plotted from its record coordinates.

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

Scope ZIP code 21918. 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.