| St. Charles County is a county located | | | | which 40.50% had children under the age |
| in the U.S. state of Missouri. As of | | | | of 18 living with them, 63.20% were |
| 2000, the population was 283,883. Saint | | | | married couples living together, 9.20% |
| Charles County is part of the St. Louis | | | | have a woman whose husband does not live |
| Metro Area. Its county seat is Saint | | | | with her, and 24.20% were non-families. |
| Charles6. The county was organized in | | | | 19.40% of all households were made up of |
| 1812 and named for the Spanish district | | | | individuals and 5.90% had someone living |
| once located here, San Carlos, from | | | | alone who was 65 years of age or older. |
| Saint Charles Borromeo. | | | | The average household size was 2.76 and |
| Geography | | | | the average family size was 3.18. |
| The county has a total area of 1,534 | | | | In the county the population was spread |
| km² (592 mi²). 1,451 km² (560 mi²) | | | | out with 29.00% under the age of 18, |
| of it is land and 83 km² (32 mi²) of | | | | 8.20% from 18 to 24, 32.60% from 25 to |
| it (5.39%) is water. | | | | 44, 21.60% from 45 to 64, and 8.80% who |
| Adjacent counties | | | | were 65 years of age or older. The |
| Lincoln County (northwest) | | | | median age was 34 years. For every 100 |
| Calhoun County, Illinois (north) | | | | females there were 97.10 males. For |
| Jersey County, Illinois (northeast) | | | | every 100 females age 18 and over, there |
| Madison County, Illinois (east) | | | | were 94.10 males. |
| St. Louis County (southeast) | | | | The median income for a household in the |
| Franklin County (south) | | | | county was $57,258, and the median |
| Warren County (west) | | | | income for a family was $64,415. Males |
| Major highways | | | | had a median income of $44,528 versus |
| Interstate 64 | | | | $29,405 for females. The per capita |
| Interstate 70 | | | | income for the county was $23,592. 4.00% |
| U.S. Route 40 | | | | of the population and 2.80% of families |
| U.S. Route 61 | | | | were below the poverty line. Out of the |
| U.S. Route 67 | | | | total people living in poverty, 4.90% |
| Route 79 | | | | are under the age of 18 and 5.10% are 65 |
| Route 94 | | | | or older. |
| Route 364 | | | | St. Charles County, with a population of |
| Route 370 | | | | 337,572, has been one of the |
| Demographics | | | | fastest-growing counties in the country |
| As of 2000, there were 283,883 people, | | | | for decades, with 55 percent growth in |
| 101,663 households, and 77,060 families | | | | the 1980s, 33 percent in the 1990s, and |
| residing in the county. The population | | | | another 13 percent between 2000 and |
| density was 196/km² (507/mi²). There | | | | 2004. The county features a |
| were 105,514 housing units at an average | | | | cross-section of industry, as well as |
| density of 73 persons/km² (188 persons | | | | extensive retail and some agriculture. |
| mi²). The racial makeup of the county | | | | With the Missouri River on the south and |
| was 94.67% White, 2.69% African | | | | the Mississippi on the north and east, |
| American, 0.23% Native American, 0.85% | | | | the county is bisected east to west by |
| Asian, 0.03% Pacific Islander, 0.46% | | | | Interstate 70. St. Charles County has |
| from other races, and 1.07% from two or | | | | two small airports and two ferries that |
| more races. Hispanic or Latino of any | | | | cross the Mississippi River. The City of |
| race were 1.47% of the population. | | | | St. Charles is the county seat. |
| There were 101,663 households out of | | | | |