ZIP Code 61104 — Rockford, IL
61104 is a standard (street delivery) ZIP code serving Rockford, Illinois, in Winnebago 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 61104 at a glance
| ZIP code | 61104 |
|---|---|
| Primary city | Rockford |
| State | Illinois (IL) |
| County | Winnebago FIPS 17201 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 17,222 |
| Coordinates | 42.251860, -89.079110 |
How ZIP+4 works in 61104
The four digits after the hyphen encode a delivery segment inside 61104. 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 61104 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 Rockford
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 61104.
| ZIP | City | Distance |
|---|---|---|
| 61108 | Rockford, IL | 3.9 mi |
| 61102 | Rockford, IL | 4.2 mi |
| 61109 | Rockford, IL | 4.3 mi |
| 61107 | Rockford, IL | 4.4 mi |
| 61112 | Rockford, IL | 5.3 mi |
| 61114 | Rockford, IL | 6 mi |
| 61103 | Rockford, IL | 6.4 mi |
| 61101 | Rockford, IL | 6.8 mi |
| 61111 | Loves Park, IL | 6.9 mi |
| 61016 | Cherry Valley, IL | 7.7 mi |
| 61115 | Machesney Park, IL | 8.1 mi |
| 61088 | Winnebago, IL | 9.1 mi |
Questions about 61104
What is the ZIP+4 code for 61104?
61104 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 61104, you need to look up a specific street address to get them.
What city is 61104?
61104 is assigned to Rockford, Illinois, in Winnebago 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.