| City : | O'fallon City |
| County : | St. Charles County |
| State : | Missouri (MO) |
| | |
| Land Area : | 29.19 sq mi |
| Water Area : | 0.00 sq mi |
| Latitude : | 38.7835042 |
| Longitude : | -90.7153509 |
| | |
| Population (2010): | 79,329 |
| Population Estimate (2012) : | 79,073 |
| Population Density : | 2,717.82/sq mi |
| Housing Units (2012) : | 29,376 |
| Median Household Income (2012) : | $77,210 (Missouri : $47,333, USA : $53,046) |
| Median Family Income (2012) : | $88,799 (Missouri : $59,395, USA : $64,585) |
| Median House Price (2012) : | $199,300 (Missouri : $138,400, USA : $181,400) |