| County : | St. Charles County |
| State : | Missouri (MO) |
| Land Area : | 560.43 sq mi |
| Water Area : | 32.17 sq mi |
| Latitude : | 38.7811023 |
| Longitude : | -90.6749153 |
| Population (2010): | 360,485 |
| Population Estimate (2012) : | 360,695 |
| Population Density : | 643.23/sq mi |
| Housing Units (2012) : | 141,016 |
| Median Household Income (2012) : | $71,416 (Missouri : $47,333, USA : $53,046) |
| Median Family Income (2012) : | $84,184 (Missouri : $59,395, USA : $64,585) |
| Median House Price (2012) : | $193,600 (Missouri : $138,400, USA : $181,400) |
St. Charles County Cities / Towns
| Augusta Town (253) | Cottleville City (3,075) | Dardenne Prairie City (11,494) |
| Defiance (155) | Flint Hill City (525) | Foristell City (505) |
| Josephville Village (376) | Lake St. Louis City (14,545) | New Melle City (475) |
| O'fallon City (79,329) | Portage Des Sioux City (328) | St. Charles City (65,794) |
| St. Paul City (1,829) | St. Peters City (52,575) | Weldon Spring City (5,443) |
| Weldon Spring Heights Town (91) | Wentzville City (29,070) | West Alton City (522) |
St. Charles County Zip Codes
| 63301 (48,514) | 63303 (45,834) | 63304 (40,336) |
| 63332 (1,292) | 63341 (3,530) | 63348 (6,059) |
| 63357 (5,534) | 63366 (46,175) | 63367 (19,433) |
| 63368 (43,360) | 63373 (603) | 63376 (70,828) |
| 63385 (35,750) | 63386 (538) |