Massachusetts ZIP codes

All 685 ZIPs in Massachusetts, 01001 to 05544. Tap one on the map or in the list.

685

ZIP codes

7,043,978

people live in them

counties

146

PO Box & no-area ZIPs

Most people

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All 685 Massachusetts ZIP codes

ZIP codes by county

Pick a county for its ZIP list and map. Counts include ZIPs that only partly reach into the county.

Questions people actually ask

How many ZIP codes are in Massachusetts?

685 ZIP codes are in use in Massachusetts. 539 cover a delivery area, and 146 are PO Box, single-building or organization ZIPs with no area of their own.

What do Massachusetts ZIP codes start with?

Massachusetts ZIP codes start with these three-digit prefixes: 010–027, 055. Each prefix is a mail sorting area run from one processing center.

Which Massachusetts ZIP code has the most people?

02301 in Brockton has the most residents of any Massachusetts ZIP, about 68,969 people in the Census Bureau’s ACS 2020–2024 estimates.

Which Massachusetts county has the most ZIP codes?

Middlesex County touches 111 ZIP codes, the most of the 14 counties in Massachusetts. 23 Massachusetts ZIPs reach into more than one county.

Are these the official USPS ZIP code boundaries?

The map uses Census ZIP Code Tabulation Areas, the standard public stand-in for USPS delivery areas. They match for almost every home. For a mailing address, the USPS ZIP Code lookup has the final word.

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Updated 2026-11-10 · Where the data comes from