ZIP Code 37166 — Smithville, TN
37166 is a standard (street delivery) ZIP code serving Smithville, Tennessee, in DeKalb 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 37166 at a glance
| ZIP code | 37166 |
|---|---|
| Primary city | Smithville |
| State | Tennessee (TN) |
| County | DeKalb FIPS 47041 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 15,731 |
| Coordinates | 35.924440, -85.789780 |
How ZIP+4 works in 37166
The four digits after the hyphen encode a delivery segment inside 37166. 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 37166 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 37166.
| ZIP | City | Distance |
|---|---|---|
| 37059 | Dowelltown, TN | 7.9 mi |
| 37095 | Liberty, TN | 10.3 mi |
| 38587 | Walling, TN | 10.4 mi |
| 38582 | Silver Point, TN | 11.9 mi |
| 38569 | Lancaster, TN | 13.3 mi |
| 38550 | Campaign, TN | 13.8 mi |
| 38579 | Quebeck, TN | 14.9 mi |
| 38544 | Baxter, TN | 15 mi |
| 37190 | Woodbury, TN | 15.7 mi |
| 37012 | Alexandria, TN | 15.7 mi |
| 38581 | Rock Island, TN | 15.9 mi |
| 38567 | Hickman, TN | 16.1 mi |
Questions about 37166
What is the ZIP+4 code for 37166?
37166 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 37166, you need to look up a specific street address to get them.
What city is 37166?
37166 is assigned to Smithville, Tennessee, in DeKalb 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.