ZIP Code 61370 — Tonica, IL
61370 is a standard (street delivery) ZIP code serving Tonica, Illinois, in LaSalle 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 61370 at a glance
| ZIP code | 61370 |
|---|---|
| Primary city | Tonica |
| State | Illinois (IL) |
| County | LaSalle FIPS 17099 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 1,215 |
| Coordinates | 41.208540, -89.034760 |
How ZIP+4 works in 61370
The four digits after the hyphen encode a delivery segment inside 61370. 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 61370 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 61370.
| ZIP | City | Distance |
|---|---|---|
| 61332 | Leonore, IL | 2.9 mi |
| 61348 | Oglesby, IL | 5 mi |
| 61334 | Lostant, IL | 5.4 mi |
| 61316 | Cedar Point, IL | 5.8 mi |
| 61363 | Standard, IL | 8.3 mi |
| 61326 | Granville, IL | 10.1 mi |
| 61354 | Peru, IL | 10.2 mi |
| 61377 | Wenona, IL | 10.4 mi |
| 61335 | Mcnabb, IL | 10.8 mi |
| 61364 | Streator, IL | 11 mi |
| 61325 | Grand Ridge, IL | 11.8 mi |
| 61336 | Magnolia, IL | 11.8 mi |
Questions about 61370
What is the ZIP+4 code for 61370?
61370 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 61370, you need to look up a specific street address to get them.
What city is 61370?
61370 is assigned to Tonica, Illinois, in LaSalle 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.