County ZIP codes · Illinois · FIPS 17201
Winnebago County, IL ZIP Codes
Winnebago County, Illinois has 33 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026): 25 residential and 8 for PO boxes or a single organization. 20 of the residential ones lie mainly in Winnebago County and 5 mainly in a neighboring county; 14 cross the county line. Median household income ranges from $33,772 in 61104 (Rockford) to $127,273 in 61011 (Caledonia) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of Winnebago County?
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).
How different are its ZIP codes?
The middle half of its ranked ZIP codes (1,000+ people living in households) report median household incomes between $62,973 and $98,088.
They carry 17 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 25 residential ZIP codes in Winnebago County
20 ZIP codes lie mainly in Winnebago County; 5 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 61107 | Rockford | 30,765 | 2,062 | $79k | $175k | 94% |
| 61108 | Rockford | 30,355 | 2,781 | $64k | $145k | 100% |
| 61109 | Rockford | 26,768 | 695 | $63k | $139k | 97% |
| 61111 | Loves Park | 23,286 | 1,637 | $61k | $159k | 96% |
| 61103 | Rockford | 22,869 | 1,400 | $51k | $116k | 100% |
| 61115 | Machesney Park | 22,364 | 2,100 | $75k | $173k | 100% |
| 61073 | Roscoe | 20,194 | 723 | $102k | $239k | 96% |
| 61101 | Rockford | 19,318 | 465 | $46k | $91k | 100% |
| 61104 | Rockford | 17,222 | 3,827 | $34k | $90k | 100% |
| 61102 | Rockford | 15,937 | 467 | $47k | $99k | 88% |
| 61114 | Rockford | 15,325 | 1,882 | $86k | $204k | 88% |
| 61072 | Rockton | 11,285 | 216 | $105k | $238k | 100% |
| 61080 | South Beloit | 10,955 | 437 | $77k | $181k | 71% |
| 61088 | Winnebago | 6,167 | 109 | $98k | $209k | 100% |
| 61016 | Cherry Valley | 5,465 | 193 | $85k | $231k | 57% |
| 61063 | Pecatonica | 4,011 | 54 | $84k | $174k | 84% |
| 61024 | Durand | 2,318 | 39 | $71k | $153k | 100% |
| 61079 | Shirland | 210 | 54 | $46k | $123k | 100% |
| 61112 | Rockford | 152 | 193 | $41k | – | 100% |
| 61077 | Seward | 97 | 122 | – | – | 100% |
Partly in Winnebago County
| In this county | ||||||
|---|---|---|---|---|---|---|
| 61019 | Davis | 3,461 | 93 | $105k | $232k | 38% |
| 61011 | Caledonia | 2,676 | 69 | $127k | $312k | 18% |
| 61020 | Davis Junction | 3,149 | 100 | $106k | $203k | 9% |
| 61084 | Stillman Valley | 3,201 | 92 | $103k | $214k | 7% |
| 61047 | Leaf River | 1,622 | 24 | $86k | $242k | 6% |
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; county shares by land area (Census 2020 ZCTA-county relationship file).
Which ZIP codes cross the county line?
14 ZIP codes of Winnebago County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In Winnebago | Elsewhere |
|---|---|---|
| 61107 | 94% | Boone County 6% |
| 61109 | 97% | Ogle County 3% |
| 61111 | 96% | Boone County 4% |
| 61073 | 96% | Boone County 4% |
| 61102 | 88% | Ogle County 12% |
| 61114 | 88% | Boone County 12% |
| 61080 | 71% | Boone County 29% |
| 61016 | 57% | Boone County 43% |
| 61063 | 84% | Stephenson County 16% |
| 61019 | 38% | Stephenson County 62% |
| 61084 | 7% | Ogle County 93% |
| 61020 | 9% | Ogle County 91% |
| 61011 | 18% | Boone County 82% |
| 61047 | 6% | Ogle County 92%; Stephenson County 2% |
Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).
PO Box and single-organization ZIP codes
Source: GeoNames postal codes (CC BY 4.0).
Which first three digits do Winnebago County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Winnebago County's ZIP codes use 2 prefixes: 610 and 611.
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.