Newmarket New Hampshire ZIP Codes

Newmarket holds a single ZIP code.

Every ZIP code in Newmarket

The complete list of Newmarket, New Hampshire ZIP codes with the county each falls in.
ZIP code	County
03857	Rockingham County

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP. USPS delivery-type products are licensed, and no clean-rights source maps ZIP codes to neighbourhoods — so the Newmarket codes above are listed without a column we would have to invent.

Scope every ZIP code recorded for Newmarket. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated 15 July 2026. ZIP codes are delivery-route groupings, not areas; the boundaries implied by any ZIP map are approximations.

How these codes cluster

Every Newmarket ZIP code begins 038. Those first three digits identify the sectional center facility that processes mail for this part of New Hampshire. Statewide that range covers 77 ZIP codes, so Newmarket accounts for 1% of it.

Every New Hampshire ZIP prefix and the region it covers →

Area codes covering Newmarket

ZIP codes and area codes are separate systems — one routes mail, the other routes calls — and they do not share boundaries. The code below serves the same ground Newmarket occupies.

603 Area code 603

Newmarket New Hampshire area codes in full →

Where Newmarket's ZIP codes sit

Each point is one Newmarket ZIP code, plotted from its record coordinates.

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

Cities near Newmarket

The closest places to Newmarket with their own ZIP code list, nearest first.
City	Distance	ZIP codes
Lee New Hampshire ZIP codes	4.1 mi	1 ZIP code
Stratham New Hampshire ZIP codes	4.4 mi	1 ZIP code
Greenland New Hampshire ZIP codes	5.5 mi	1 ZIP code
Madbury New Hampshire ZIP codes	6.7 mi	1 ZIP code
Portsmouth New Hampshire ZIP codes	8.2 mi	4 ZIP codes
Dover New Hampshire ZIP codes	8.2 mi	3 ZIP codes
Epping New Hampshire ZIP codes	8.4 mi	1 ZIP code
Nottingham New Hampshire ZIP codes	9.1 mi	1 ZIP code

Straight-line distance between place reference points, not driving distance. Where a place has no Census Gazetteer point, its postal centroid is used instead.