Chelmsford Massachusetts ZIP Codes

Chelmsford holds a single ZIP code.

We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP.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 Chelmsford codes above are listed without a column we would have to invent.

Scope every ZIP code recorded for Chelmsford. 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.

Every Chelmsford ZIP code begins 018. Those first three digits identify the sectional center facility that processes mail for this part of Massachusetts. Statewide that range covers 47 ZIP codes, so Chelmsford accounts for 2% of it.

Every Massachusetts ZIP prefix and the region it covers →

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

• 351 Area code 351
• 978 Area code 978

Chelmsford Massachusetts area codes in full →

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