ZIP Code 37921 — Knoxville, TN
37921 is a standard (street delivery) ZIP code serving Knoxville, 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 37921 at a glance
| ZIP code | 37921 |
|---|---|
| Primary city | Knoxville |
| State | Tennessee (TN) |
| County | Knox FIPS 47093 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 28,717 |
| Coordinates | 35.978770, -84.000280 |
How ZIP+4 works in 37921
The four digits after the hyphen encode a delivery segment inside 37921. 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 37921 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 Knoxville
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 37921.
| ZIP | City | Distance |
|---|---|---|
| 37912 | Knoxville, TN | 2.2 mi |
| 37909 | Knoxville, TN | 2.5 mi |
| 37916 | Knoxville, TN | 4.1 mi |
| 37919 | Knoxville, TN | 4.4 mi |
| 37902 | Knoxville, TN | 4.6 mi |
| 37929 | Knoxville, TN | 4.8 mi |
| 37917 | Knoxville, TN | 5.1 mi |
| 37915 | Knoxville, TN | 5.6 mi |
| 37923 | Knoxville, TN | 5.7 mi |
| 37849 | Powell, TN | 6 mi |
| 37931 | Knoxville, TN | 7 mi |
| 37918 | Knoxville, TN | 7.5 mi |
Questions about 37921
What is the ZIP+4 code for 37921?
37921 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 37921, you need to look up a specific street address to get them.
What city is 37921?
37921 is assigned to Knoxville, 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.