ZIP Code 37721 — Corryton, TN
37721 is a standard (street delivery) ZIP code serving Corryton, Tennessee, in Knox 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 37721 at a glance
| ZIP code | 37721 |
|---|---|
| Primary city | Corryton |
| State | Tennessee (TN) |
| County | Knox FIPS 47093 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 14,306 |
| Coordinates | 36.131550, -83.808290 |
How ZIP+4 works in 37721
The four digits after the hyphen encode a delivery segment inside 37721. 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 37721 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 37721.
| ZIP | City | Distance |
|---|---|---|
| 37806 | Mascot, TN | 5.6 mi |
| 37779 | Luttrell, TN | 6.2 mi |
| 37924 | Knoxville, TN | 6.6 mi |
| 37938 | Knoxville, TN | 7.3 mi |
| 37918 | Knoxville, TN | 7.6 mi |
| 37709 | Blaine, TN | 8.4 mi |
| 37807 | Maynardville, TN | 8.9 mi |
| 37871 | Strawberry Plains, TN | 9.3 mi |
| 37848 | Powder Springs, TN | 10.1 mi |
| 37914 | Knoxville, TN | 10.5 mi |
| 37917 | Knoxville, TN | 10.7 mi |
| 37915 | Knoxville, TN | 12.2 mi |
Questions about 37721
What is the ZIP+4 code for 37721?
37721 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 37721, you need to look up a specific street address to get them.
What city is 37721?
37721 is assigned to Corryton, Tennessee, in Knox 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.