ZIP Code 21639

21639 is one of Maryland's ZIP codes, delivering to addresses in Greensboro, Caroline County.

City: Greensboro
County: Caroline County
State: Maryland
Prefix: 216xx

Where this code sits

21639 is part of the 216xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Greensboro.

Greensboro Maryland ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 21639 delivers to without sharing its boundary.

ZIP codes nearest 21639

The ZIP codes whose reference points sit closest to 21639.
ZIP code	Distance	Delivers to
ZIP code 21660	4.3 mi	Ridgely, MD
ZIP code 21636	4.3 mi	Goldsboro, MD
ZIP code 21629	7.2 mi	Denton, MD
ZIP code 21640	7.3 mi	Henderson, MD
ZIP code 21641	7.7 mi	Hillsboro, MD
ZIP code 21657	9.3 mi	Queen Anne, MD
ZIP code 21649	10 mi	Marydel, MD
ZIP code 19964	10 mi	Marydel, DE

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 21639, plotted from its record coordinates.

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

Scope ZIP code 21639. 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.