St. Charles County, Missouri ZIP codes
17 ZIP codes are in St. Charles County, plus 1 that cross in from neighboring counties. It's part of the St. Louis, MO-IL metro area.
- ZIP codes
- 17
- Population in these ZIPs
- 416,486
- Avg. median income
- $107,100population-weighted
- Cities & towns
- 13
Click anywhere on the map to see which ZIP code it's in.
ZIP codes in St. Charles County
| ZIP code | City | Population | Median income | Typical home value |
|---|---|---|---|---|
| 63301 | Saint Charles | 52,667 | $85,308 | $317,600 |
| 63302 PO Box | Saint Charles | — | — | — |
| 63303 | Saint Charles | 46,089 | $99,138 | $355,800 |
| 63304 | Saint Charles | 43,195 | $114,442 | $401,400 |
| 63332 | Augusta | 1,651 | $146,146 | $560,800 |
| 63338 PO Box | Cottleville | — | — | — |
| 63341 | Defiance | 3,515 | $170,598 | $636,200 |
| 63346 PO Box | Flinthill | — | — | — |
| 63348 | Foristell | 10,394 | $115,661 | $452,900 |
| 63365 | New Melle | 51 | $53,542 | — |
| 63366 | O Fallon | 54,769 | $100,621 | $363,600 |
| 63367 | Lake Saint Louis | 29,725 | $137,648 | $442,800 |
| 63368 | O Fallon | 46,966 | $124,297 | $415,600 |
| 63373 | Portage Des Sioux | 690 | $88,750 | $242,300 |
| 63376 | Saint Peters | 74,962 | $96,393 | $328,200 |
| 63385 | Wentzville | 51,330 | $112,199 | $403,400 |
| 63386 | West Alton | 482 | $110,250 | $169,700 |
ZIP codes partly in St. Charles County
These ZIP codes are mostly in a neighboring county but cover part of St. Charles County.
| ZIP code | City | County | Population | Median income | Typical home value |
|---|---|---|---|---|---|
| 63357 | Marthasville | Warren County | 6,536 | $92,200 | $343,600 |
Population and median household income: ACS 2020–2024 5-year estimates. Typical home value: Zillow Home Value Index (September 2026) where available, otherwise the ACS median owner-reported value. "PO Box" marks ZIP codes with no delivery area of their own. Methodology
Cities and towns in St. Charles County
Nearby counties
Frequently asked questions
How many ZIP codes are in St. Charles County, Missouri?
17 ZIP codes are mainly in St. Charles County, and 1 more ZIP codes from neighboring areas reach partly into it.
What cities are in St. Charles County?
ZIP codes in St. Charles County use the city names Augusta, Cottleville, Defiance, Flinthill, Foristell, Lake Saint Louis, New Melle, O Fallon, Portage Des Sioux, Saint Charles, Saint Peters and Wentzville and others.
What metro area is St. Charles County in?
St. Charles County is part of the St. Louis, MO-IL metropolitan statistical area.