O'Fallon, Missouri ZIP Codes
- ZIP records
2 - Sum of listed ZIP population estimates
101,735 - Counties represented
1 - Population range
46,966–54,769 per ZIP
Population sum includes positive estimates in these ZIP records; it is not an official city population.
Top ZIP Codes by Population
| Rank | ZIP Code | City | County | Population estimate |
|---|---|---|---|---|
| 1 | 63366 | O'Fallon | St. Charles | 54,769 |
| 2 | 63368 | O'Fallon | St. Charles | 46,966 |
Counties represented
All ZIP Codes in O'Fallon
Browse all ZIP data for Missouri
Methodology: ZIP records are grouped by the source file's primary city and state fields. Population ranges and sums use positive ZIP-level estimates; sums should not be read as official city totals. County links use each record's listed county assignment.