County ZIP codes · Illinois · FIPS 17163
St. Clair County, IL ZIP Codes
St. Clair County, Illinois has 37 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026): 34 residential and 3 for PO boxes or a single organization. 27 of the residential ones lie mainly in St. Clair County and 7 mainly in a neighboring county; 11 cross the county line. Median household income ranges from $29,845 in 62207 (East Saint Louis) to $136,345 in 62285 (Smithton) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of St. Clair 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 $65,952 and $101,155.
They carry 26 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 34 residential ZIP codes in St. Clair County
27 ZIP codes lie mainly in St. Clair County; 7 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 62269 | O Fallon | 35,923 | 1,204 | $104k | $292k | 100% |
| 62221 | Belleville | 29,875 | 854 | $82k | $218k | 100% |
| 62226 | Belleville | 28,255 | 2,037 | $71k | $167k | 100% |
| 62220 | Belleville | 19,152 | 663 | $66k | $157k | 100% |
| 62208 | Fairview Heights | 16,821 | 1,256 | $80k | $176k | 100% |
| 62223 | Belleville | 16,269 | 634 | $74k | $159k | 100% |
| 62206 | East Saint Louis | 12,959 | 891 | $34k | $53k | 100% |
| 62258 | Mascoutah | 10,437 | 138 | $95k | $233k | 100% |
| 62232 | Caseyville | 7,063 | 551 | $64k | $125k | 100% |
| 62207 | East Saint Louis | 6,984 | 1,126 | $30k | $58k | 100% |
| 62254 | Lebanon | 6,710 | 164 | $97k | $218k | 98% |
| 62260 | Millstadt | 6,668 | 152 | $91k | $253k | 100% |
| 62205 | East Saint Louis | 6,459 | 1,016 | $46k | $42k | 100% |
| 62243 | Freeburg | 6,418 | 124 | $103k | $280k | 100% |
| 62203 | East Saint Louis | 5,465 | 967 | $42k | $69k | 100% |
| 62225 | Scott Air Force Base | 5,242 | 999 | $103k | – | 100% |
| 62201 | East Saint Louis | 4,921 | 409 | $27k | $60k | 96% |
| 62285 | Smithton | 4,239 | 261 | $136k | $274k | 100% |
| 62239 | Dupo | 4,232 | 495 | $61k | $111k | 100% |
| 62204 | East Saint Louis | 4,055 | 878 | $35k | $48k | 100% |
| 62264 | New Athens | 3,097 | 47 | $57k | $127k | 94% |
| 62257 | Marissa | 2,046 | 25 | $79k | $138k | 57% |
| 62240 | East Carondelet | 1,796 | 121 | $96k | $89k | 100% |
| 62255 | Lenzburg | 1,092 | 41 | $81k | $161k | 100% |
| 62059 | Lovejoy | 729 | 1,110 | $31k | $38k | 100% |
| 62282 | Saint Libory | 563 | 293 | $117k | $179k | 100% |
| 62289 | Summerfield | 273 | 182 | $47k | $65k | 100% |
Partly in St. Clair County
| In this county | ||||||
|---|---|---|---|---|---|---|
| 62293 | Trenton | 4,433 | 85 | $98k | $251k | 37% |
| 62236 | Columbia | 14,154 | 235 | $109k | $307k | 18% |
| 62234 | Collinsville | 31,648 | 849 | $70k | $170k | 17% |
| 62265 | New Baden | 4,555 | 135 | $85k | $195k | 14% |
| 62298 | Waterloo | 18,208 | 127 | $101k | $290k | 9% |
| 62060 | Madison | 3,558 | 1,007 | $47k | $63k | 5% |
| 62294 | Troy | 15,325 | 520 | $121k | $276k | 3% |
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?
11 ZIP codes of St. Clair County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In St. Clair | Elsewhere |
|---|---|---|
| 62234 | 17% | Madison County 83% |
| 62298 | 9% | Monroe County 91% |
| 62294 | 3% | Madison County 97% |
| 62236 | 18% | Monroe County 82% |
| 62254 | 98% | Madison County 2% |
| 62201 | 96% | Madison County 4% |
| 62265 | 14% | Clinton County 86% |
| 62293 | 37% | Clinton County 46%; Madison County 16% |
| 62060 | 5% | Madison County 95% |
| 62264 | 94% | Monroe County 6% |
| 62257 | 57% | Washington County 36%; Randolph County 7% |
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 St. Clair County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. St. Clair County's ZIP codes use 2 prefixes: 620 and 622.
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.