ZIP Code 20170 — Herndon, VA
20170 is a standard (street delivery) ZIP code serving Herndon, Virginia, in Fairfax 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 20170 at a glance
| ZIP code | 20170 |
|---|---|
| Primary city | Herndon |
| State | Virginia (VA) |
| County | Fairfax FIPS 51059 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 43,866 |
| Coordinates | 38.980750, -77.380420 |
How ZIP+4 works in 20170
The four digits after the hyphen encode a delivery segment inside 20170. 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 20170 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 Herndon
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 20170.
| ZIP | City | Distance |
|---|---|---|
| 20194 | Reston, VA | 2 mi |
| 20164 | Sterling, VA | 2.3 mi |
| 20190 | Reston, VA | 2.7 mi |
| 20191 | Reston, VA | 3.5 mi |
| 20171 | Herndon, VA | 4 mi |
| 20166 | Sterling, VA | 4.5 mi |
| 22066 | Great Falls, VA | 4.6 mi |
| 20165 | Sterling, VA | 4.8 mi |
| 22182 | Vienna, VA | 6.5 mi |
| 20147 | Ashburn, VA | 6.8 mi |
| 22124 | Oakton, VA | 6.8 mi |
| 20151 | Chantilly, VA | 6.8 mi |
Questions about 20170
What is the ZIP+4 code for 20170?
20170 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 20170, you need to look up a specific street address to get them.
What city is 20170?
20170 is assigned to Herndon, Virginia, in Fairfax 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.