ZIP Code 02421 — Lexington, MA
02421 is a standard (street delivery) ZIP code serving Lexington, Massachusetts, in Middlesex 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 02421 at a glance
| ZIP code | 02421 |
|---|---|
| Primary city | Lexington |
| State | Massachusetts (MA) |
| County | Middlesex FIPS 25017 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 18,080 |
| Coordinates | 42.438000, -71.239220 |
How ZIP+4 works in 02421
The four digits after the hyphen encode a delivery segment inside 02421. 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 02421 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 Lexington
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 02421.
| ZIP | City | Distance |
|---|---|---|
| 02420 | Lexington, MA | 1.8 mi |
| 01731 | Hanscom Afb, MA | 2.8 mi |
| 02451 | Waltham, MA | 2.9 mi |
| 02452 | Waltham, MA | 3.2 mi |
| 02476 | Arlington, MA | 3.6 mi |
| 01773 | Lincoln, MA | 3.7 mi |
| 02478 | Belmont, MA | 4.2 mi |
| 02474 | Arlington, MA | 4.4 mi |
| 02453 | Waltham, MA | 4.7 mi |
| 01730 | Bedford, MA | 4.7 mi |
| 01890 | Winchester, MA | 4.8 mi |
| 01803 | Burlington, MA | 4.9 mi |
Questions about 02421
What is the ZIP+4 code for 02421?
02421 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 02421, you need to look up a specific street address to get them.
What city is 02421?
02421 is assigned to Lexington, Massachusetts, in Middlesex 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.