County ZIP codes · Illinois · FIPS 17103
Lee County, IL ZIP Codes
Lee County, Illinois has 24 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 14 of the residential ones lie mainly in Lee County and 10 mainly in a neighboring county; 14 cross the county line. Median household income ranges from $60,508 in 61071 (Rock Falls) to $75,938 in 61006 (Ashton) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of Lee 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 $67,586 and $73,214.
They carry 24 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 24 residential ZIP codes in Lee County
14 ZIP codes lie mainly in Lee County; 10 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 61021 | Dixon | 22,308 | 149 | $69k | $149k | 90% |
| 61310 | Amboy | 3,347 | 31 | $70k | $166k | 100% |
| 61006 | Ashton | 1,541 | 22 | $76k | $156k | 73% |
| 61031 | Franklin Grove | 1,492 | 33 | $75k | $137k | 95% |
| 61353 | Paw Paw | 1,282 | 40 | $67k | $165k | 100% |
| 60530 | Lee | 992 | 36 | $96k | $265k | 68% |
| 61367 | Sublette | 843 | 19 | $61k | $160k | 100% |
| 60553 | Steward | 722 | 15 | $109k | $177k | 100% |
| 61318 | Compton | 595 | 18 | $63k | $97k | 100% |
| 61378 | West Brooklyn | 513 | 8 | $85k | $189k | 100% |
| 61042 | Harmon | 404 | 6 | $71k | $154k | 100% |
| 61324 | Eldena | 97 | 471 | – | – | 100% |
| 61057 | Nachusa | 30 | 47 | – | – | 100% |
| 61331 | Lee Center | no residents | 0 | – | – | 100% |
Partly in Lee County
| In this county | ||||||
|---|---|---|---|---|---|---|
| 61349 | Ohio | 1,151 | 19 | $71k | $119k | 27% |
| 61376 | Walnut | 1,894 | 19 | $61k | $128k | 14% |
| 61071 | Rock Falls | 13,581 | 187 | $61k | $102k | 11% |
| 61068 | Rochelle | 14,788 | 123 | $73k | $171k | 10% |
| 60518 | Earlville | 3,289 | 25 | $70k | $166k | 9% |
| 61330 | La Moille | 1,182 | 16 | $69k | $148k | 8% |
| 61081 | Sterling | 20,844 | 168 | $68k | $123k | 5% |
| 61342 | Mendota | 8,543 | 79 | $65k | $154k | 5% |
| 61243 | Deer Grove | 155 | 6 | $148k | $173k | 5% |
| 61064 | Polo | 3,757 | 35 | $75k | $164k | 1% |
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 Lee County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In Lee | Elsewhere |
|---|---|---|
| 61021 | 90% | Ogle County 10% |
| 61081 | 5% | Whiteside County 95% |
| 61068 | 10% | Ogle County 89%; DeKalb County 1% |
| 61071 | 11% | Whiteside County 89% |
| 61342 | 5% | LaSalle County 87%; Bureau County 8% |
| 61064 | 1% | Ogle County 94%; Carroll County 4% |
| 60518 | 9% | LaSalle County 66%; DeKalb County 25% |
| 61376 | 14% | Bureau County 86% |
| 61006 | 73% | Ogle County 27% |
| 61031 | 95% | Ogle County 5% |
| 61330 | 8% | Bureau County 92% |
| 61349 | 27% | Bureau County 73% |
| 60530 | 68% | DeKalb County 32% |
| 61243 | 5% | Whiteside County 95% |
Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).
Which first three digits do Lee County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Lee County's ZIP codes use 4 prefixes: 605, 610, 612 and 613.
| Prefix | Sectional center | Here | All codes |
|---|---|---|---|
| 605 | Fox Valley, IL (SCF 605) | 3 | 65 |
| 610 | Palatine, IL (SCF 600) | 9 | 66 |
| 612 | Quad Cities, IL (SCF 612) | 1 | 47 |
| 613 | Peoria, IL (SCF 615) | 11 | 62 |
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.