ZIP Code 01720 — Acton, MA
01720 is a standard (street delivery) ZIP code serving Acton, 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 01720 at a glance
| ZIP code | 01720 |
|---|---|
| Primary city | Acton |
| State | Massachusetts (MA) |
| County | Middlesex FIPS 25017 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 23,526 |
| Coordinates | 42.483970, -71.438090 |
How ZIP+4 works in 01720
The four digits after the hyphen encode a delivery segment inside 01720. 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 01720 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 Acton
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 01720.
| ZIP | City | Distance |
|---|---|---|
| 01718 | Acton, MA | 2.6 mi |
| 01742 | Concord, MA | 4 mi |
| 01719 | Boxborough, MA | 4.1 mi |
| 01754 | Maynard, MA | 4.1 mi |
| 01460 | Littleton, MA | 4.4 mi |
| 01775 | Stow, MA | 5.3 mi |
| 01741 | Carlisle, MA | 5.4 mi |
| 01776 | Sudbury, MA | 6.9 mi |
| 01886 | Westford, MA | 7.1 mi |
| 01451 | Harvard, MA | 7.2 mi |
| 01773 | Lincoln, MA | 7.7 mi |
| 01731 | Hanscom Afb, MA | 8.1 mi |
Questions about 01720
What is the ZIP+4 code for 01720?
01720 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 01720, you need to look up a specific street address to get them.
What city is 01720?
01720 is assigned to Acton, 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.