ZIP Code 02121 — Dorchester, MA
02121 is a standard (street delivery) ZIP code serving Dorchester, 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 02121 at a glance
| ZIP code | 02121 |
|---|---|
| Primary city | Dorchester |
| State | Massachusetts (MA) |
| County | Suffolk FIPS 25025 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 29,040 |
| Coordinates | 42.305700, -71.086930 |
How ZIP+4 works in 02121
The four digits after the hyphen encode a delivery segment inside 02121. 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 02121 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.
Other ZIP codes in Dorchester
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 02121.
| ZIP | City | Distance |
|---|---|---|
| 02119 | Roxbury, MA | 1.3 mi |
| 02130 | Jamaica Plain, MA | 1.5 mi |
| 02124 | Dorchester Center, MA | 1.6 mi |
| 02125 | Dorchester, MA | 1.7 mi |
| 02120 | Roxbury Crossing, MA | 1.9 mi |
| 02122 | Dorchester, MA | 2 mi |
| 02126 | Mattapan, MA | 2.1 mi |
| 02131 | Roslindale, MA | 2.4 mi |
| 02115 | Boston, MA | 2.4 mi |
| 02118 | Boston, MA | 2.4 mi |
| 02445 | Brookline, MA | 2.7 mi |
| 02199 | Boston, MA | 2.9 mi |
Questions about 02121
What is the ZIP+4 code for 02121?
02121 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 02121, you need to look up a specific street address to get them.
What city is 02121?
02121 is assigned to Dorchester, 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.