ZIP Code 20857

20857 is one of Maryland's ZIP codes, delivering to addresses in Rockville, Montgomery County.

City: Rockville
County: Montgomery County
State: Maryland
Prefix: 208xx

Where this code sits

20857 is part of the 208xx range, the group of codes handled by one mail processing centre. Rockville is served by 8 ZIP codes in total; the full list, with the county each falls in, is on the Rockville page.

Rockville Maryland ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 20857 delivers to without sharing its boundary.

ZIP codes nearest 20857

The ZIP codes whose reference points sit closest to 20857.
ZIP code	Distance	Delivers to
ZIP code 20847	0.0 mi	Rockville, MD
ZIP code 20849	0.0 mi	Rockville, MD
ZIP code 20883	0.4 mi	Gaithersburg, MD
ZIP code 20850	0.8 mi	Rockville, MD
ZIP code 20851	1.7 mi	Rockville, MD
ZIP code 20852	2.9 mi	Rockville, MD
ZIP code 20853	3.1 mi	Rockville, MD
ZIP code 20855	3.5 mi	Derwood, 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 20857, plotted from its record coordinates.

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

Scope ZIP code 20857. 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.