ZIP Code 02129 — Charlestown, MA
02129 is a standard (street delivery) ZIP code serving Charlestown, Massachusetts, in Suffolk County. To mail something here you only need these five digits — but the four-digit extension narrows delivery to a single point, and it is what USPS bulk postage discounts are priced on.
ZIP code 02129 at a glance
| ZIP code | 02129 |
|---|---|
| Primary city | Charlestown |
| State | Massachusetts (MA) |
| County | Suffolk FIPS 25025 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 20,032 |
| Coordinates | 42.379750, -71.061670 |
How ZIP+4 works in 02129
The four digits after the hyphen encode a delivery segment inside 02129. In practice one segment usually means:
- One side of one block — odd numbers on a street between two cross streets
- A single large building, or one floor of it
- A group of PO boxes, sometimes a single box
- A single business that receives enough mail to warrant its own code
That is why 02129 has no single ZIP+4: two neighbors across the street from each other usually have different ones. Enter a street address above and we will return the exact nine-digit code along with the standardized USPS address format.
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 02129.
| ZIP | City | Distance |
|---|---|---|
| 02109 | Boston, MA | 1.1 mi |
| 02113 | Boston, MA | 1.1 mi |
| 02114 | Boston, MA | 1.2 mi |
| 02141 | Cambridge, MA | 1.2 mi |
| 02203 | Boston, MA | 1.3 mi |
| 02133 | Boston, MA | 1.5 mi |
| 02110 | Boston, MA | 1.6 mi |
| 02142 | Cambridge, MA | 1.6 mi |
| 02108 | Boston, MA | 1.6 mi |
| 02145 | Somerville, MA | 1.7 mi |
| 02143 | Somerville, MA | 1.8 mi |
| 02150 | Chelsea, MA | 1.9 mi |
Questions about 02129
What is the ZIP+4 code for 02129?
02129 is the five-digit ZIP code. The ZIP+4 adds four more digits that identify a specific delivery point — usually one side of a city block, a single building, or a group of PO boxes. Because those four digits change from address to address within 02129, you need to look up a specific street address to get them.
What city is 02129?
02129 is assigned to Charlestown, Massachusetts, in Suffolk County.
Do I need to use the ZIP+4?
It is optional for ordinary mail, but it speeds up sorting and it is required for most USPS bulk-mail postage discounts. Many address-verification and e-commerce systems also use ZIP+4 to confirm a delivery point exists.
Need thousands of these?
Upload a CSV and get ZIP+4, county, carrier route, and delivery-point data appended to every row — or call the API directly.