ZIP Code 16635 — Duncansville, PA
16635 is a standard (street delivery) ZIP code serving Duncansville, Pennsylvania, in Blair 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 16635 at a glance
| ZIP code | 16635 |
|---|---|
| Primary city | Duncansville |
| State | Pennsylvania (PA) |
| County | Blair FIPS 42013 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 12,003 |
| Coordinates | 40.416210, -78.487430 |
How ZIP+4 works in 16635
The four digits after the hyphen encode a delivery segment inside 16635. 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 16635 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 16635.
| ZIP | City | Distance |
|---|---|---|
| 16665 | Newry, PA | 3.3 mi |
| 16699 | Cresson, PA | 4.4 mi |
| 16637 | East Freedom, PA | 5.2 mi |
| 16630 | Cresson, PA | 5.8 mi |
| 15938 | Lilly, PA | 6.2 mi |
| 16641 | Gallitzin, PA | 7.7 mi |
| 15925 | Cassandra, PA | 8.1 mi |
| 16648 | Hollidaysburg, PA | 8.3 mi |
| 15946 | Portage, PA | 8.4 mi |
| 16613 | Ashville, PA | 8.7 mi |
| 16625 | Claysburg, PA | 9.1 mi |
| 16673 | Roaring Spring, PA | 9.1 mi |
Questions about 16635
What is the ZIP+4 code for 16635?
16635 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 16635, you need to look up a specific street address to get them.
What city is 16635?
16635 is assigned to Duncansville, Pennsylvania, in Blair 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.