ZIP Code 20878

20878 is one of Maryland's ZIP codes, delivering to addresses in Gaithersburg, Montgomery County.

City

Gaithersburg

County

Montgomery County

State

Maryland

Prefix

208xx

Where this code sits

20878 is part of the 208xx range, the group of codes handled by one mail processing centre. Gaithersburg is served by 9 ZIP codes in total; the full list, with the county each falls in, is on the Gaithersburg page.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 20878 delivers to without sharing its boundary.

ZIP codes nearest 20878

The ZIP codes whose reference points sit closest to 20878.
ZIP code	Distance	Delivers to
ZIP code 20874	2.3 mi	Germantown, MD
ZIP code 20899	2.5 mi	Gaithersburg, MD
ZIP code 20813	3.2 mi	Bethesda, MD
ZIP code 20827	3.2 mi	Bethesda, MD
ZIP code 20848	3.2 mi	Rockville, MD
ZIP code 20859	3.2 mi	Potomac, MD
ZIP code 20875	3.2 mi	Germantown, MD
ZIP code 20884	3.2 mi	Gaithersburg, 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 20878, plotted from its record coordinates.

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

Scope ZIP code 20878. 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.