St. Charles County is located in the central eastern part of the U.S. state of Missouri. As of the 2020 census, the population was 405,262, making it Missouri's third-most populous county. Its county seat is St. Charles. The county was organized October 1, 1812, and named for Saint Charles Borromeo, an Italian cardinal.

St. Charles County is part of the St. Louis, MO-IL Metropolitan Statistical Area and contains many of the city's northwestern suburbs. The wealthiest county in Missouri, St. Charles County is one of the nation's fastest-growing counties.

St. Charles County includes a part of the Augusta AVA, an area of vineyards and wineries designated by the federal government in 1980 as the first American Viticultural Area. The county's rural outer edge along the south-facing bluffs above the Missouri River, is also part of the broader Missouri Rhineland.

History The County of St. Charles was originally called the District of St. Charles and had no definite limits until 1816 to 1818 when neighboring counties were formed. The borders of St. Charles are the same today as they were in 1818.

Geography

According to the U.S. Census Bureau, the county has a total area of , of which is land and (5.4%) is water.

The highest elevation is northwest of Augusta near Femme Osage Creek headwaters.USGS 1/3 Arc Second NED

Adjacent counties Lincoln County (northwest) Calhoun County, Illinois (north) Jersey County, Illinois (northeast) Madison County, Illinois (east) St. Louis County (southeast) Franklin County (south) Warren County (west)

Major highways I-64 – Major freeway in the western portion of the county. Originally U.S. Route 40, the highway was upgraded to Interstate standards in the late 2000s. The highway was re-signed as Interstate 64 from the Daniel Boone Bridge to Interstate 70 in Wentzville in 2009. I-70 – The major east–west thoroughfare in the county. It is mostly a six-lane freeway in the county, but there are sections in St. Charles and St. Peters where the Interstate widens to 11 lanes of traffic. Interstate 70 Business US-40 US-61 US-67 Rte-79 Rte-94 Rte-364 – A freeway in the southern and central portions of the county that begins at Interstate 270 in western St. Louis County and ends at Interstate 64 in Lake St. Louis. Rte-370 – A six-lane freeway that connects Interstate 70 in St. Peters and Interstate 270 in northwest St. Louis County.

National protected area Two Rivers National Wildlife Refuge (part)

Climate

Demographics

2020 census As of the 2020 census, the county had a population of 405,262, a median age of 39.3 years, 23.4% of residents under the age of 18, and 16.1% of residents 65 years of age or older. For every 100 females there were 95.6 males, and for every 100 females age 18 and over there were 93.3 males. The population density was .

The racial makeup of the county was 83.8% White, 5.2% Black or African American, 0.2% American Indian and Alaska Native, 2.8% Asian, 0.1% Native Hawaiian and Pacific Islander, 1.5% from some other race, and 6.5% from two or more races. Hispanic or Latino residents of any race comprised 4.0% of the population.

94.3% of residents lived in urban areas, while 5.7% lived in rural areas.

There were 154,851 households in the county, of which 32.8% had children under the age of 18 living with them and 22.9% had a female householder with no spouse or partner present. About 23.7% of all households were made up of individuals and 9.8% had someone living alone who was 65 years of age or older.

There were 161,144 housing units, of which 3.9% were vacant. Among occupied housing units, 78.8% were owner-occupied and 21.2% were renter-occupied. The homeowner vacancy rate was 0.8% and the rental vacancy rate was 7.1%.

Racial and ethnic composition +St. Charles County, Missouri – Racial and ethnic compositionRace / Ethnicity (NH = Non-Hispanic)Pop 1980Pop 1990Pop 2000Pop 2010 Pop 2020% 1980% 1990% 2000% 2010% 2020White alone (NH)140,241203,705266,158321,078335,87997.32%95.68%93.76%89.07%82.88%Black or African American alone (NH)1,9114,9177,57314,82720,6721.33%2.31%2.67%4.11%5.10%Native American or Alaska Native alone (NH)2745095966926230.19%0.24%0.21%0.19%0.15%Asian alone (NH)5101,3942,3977,78911,0680.35%0.65%0.84%2.16%2.73%Native Hawaiian or Pacific Islander alone (NH)x included in the Asian category in the 1980 Censusx included in the Asian category in the 1990 Census61153199xx0.02%0.04%0.05%Other race alone (NH)222742244271,3770.15%0.03%0.08%0.12%0.34%Mixed race or Multiracial (NH)x not an option in the 1980 Censusx not an option in the 1990 Census2,6985,53619,433xx0.95%1.54%4.80%Hispanic or Latino (any race)9492,3084,1769,98316,0110.66%1.08%1.47%2.77%3.95%Total144,107212,907283,883360,485405,262 100.00%100.00%100.00%100.00%100.00%

2000 census There were 101,663 households, out of which 40.50% had children under the age of 18 living with them, 63.20% were married couples living together, 9.20% have a woman whose husband does not live with her, and 24.20% were non-families. 19.40% of all households were made up of individuals, and 5.90% had someone living alone who was 65 years of age or older. The average household size was 2.76 and the average family size was 3.18.

In the county, the population was spread out in age, with 29.00% under the age of 18, 8.20% from 18 to 24, 32.60% from 25 to 44, 21.60% from 45 to 64, and 8.80% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 97.10 males. For every 100 females age 18 and over, there were 94.10 males.

The median income for a household in the county was $71,458, and the median income for a family was $64,415. Males had a median income of $44,528 versus $29,405 for females. The per capita income for the county was $23,592. 4.00% of the population and 2.80% of families were below the poverty line. Out of the total people living in poverty, 4.90% are under the age of 18 and 5.10% are 65 or older.

St. Charles County has had one of the fastest-growing populations in the state for many decades, with 55% growth in the 1970s, 48% in the 1980s, 33% in the 1990s, and another 27% in the 2000s. The county sits at a cross-section of industry, as well as extensive retail and some agriculture. With the Missouri River on the south and east and the Mississippi River on the north, the county is bisected east to west by Interstate 70. After St. Charles Airport closed in 2010, the county has one remaining small airport, St. Charles County Smartt Airport. Two ferries cross the Mississippi River from St. Charles County. Education

Public schools School districts include: – Text list

Fort Zumwalt R-II School District Francis Howell R-III School District Orchard Farm R-V School District St. Charles R-VI School District Washington School District Wentzville R-IV School District

High schools (all grades 9–12): Fort Zumwalt District Fort Zumwalt East High School – St. Peters Fort Zumwalt North High School – O'Fallon Fort Zumwalt South High School – St. Peters Fort Zumwalt West High School – O'Fallon Francis Howell District Francis Howell Central High School – Cottleville Francis Howell North High School – St. Peters Francis Howell High School – Weldon Spring Heights Orchard Farm District Orchard Farm High School – St. Charles St. Charles District St. Charles High School – St. Charles St. Charles West High School – St. Charles Wentzville District Liberty High School – Lake St. Louis Emil E. Holt High School – Wentzville Timberland High School – Wentzville

Private schools

Alternative schools Boonslick State School – St. Peters – Special Education Fort Zumwalt Hope High School – O'Fallon – Other/Alternative School – (09-12) Francis Howell Union High School – St. Charles – Other/Alternative School – (09-12) Heritage Landing – St. Peters – Other/Alternative School – (06-12) The Lead School – O'Fallon – Other/Alternative School – (K-12) Lewis & Clark Career Center – St. Charles – Vocational/Technical School – (09-12) Quest Day Treatment Center – St. Charles – Other/Alternative School – (06-12) Success Campus – St. Charles – Other/Alternative School – (09-12)

Higher education Lindenwood University – St. Charles St. Charles Community College – Cottleville

Public libraries St. Charles City-County Library District

Government St. Charles County is governed by a county executive and a county council. The county council consists of seven members, each elected from various districts in the county. The county executive is elected by the entire county. The current executive is Steve Ehlmann. He was preceded by Joe Ortwerth, who was preceded by Gene Schwendemann, the first county executive of St. Charles County under the new form of government. The executive under the old form of county government was termed a "judge." The county had 258,525 registered voters as of March 2016.

St. Charles County Ambulance District (SCCAD) is the largest such district in Missouri, serving all of St. Charles County and its population of nearly 370,000.

Law enforcement The St. Charles County Sheriff's Department (SCCSD) is responsible for court services and security, prisoner transport, civil process, and bailiffs. Until the end of 2014, SCCSD was the primary law enforcement agency serving unincorporated areas of St. Charles County. On January 1, 2015, the St. Charles County Police Department was established and assumed that responsibility. It should not be confused with the St. Charles City Police Department. The St. Charles County Regional SWAT Team is made up of officers from each county law enforcement agency.

The SCCPD Aviation Unit is part of a multi-jurisdictional unit known as the Metro Air Support Unit, with the Metropolitan Police Department, City of St. Louis; St. Louis County Police Department; and St. Charles County Police Department. As of 2024, the fleet included five helicopters, and twelve pilots or pilots in training.

In May 2022, Ryan Keuhner, who was then an SCCSD deputy, shot and killed his neighbor's 3-year-old rescue dog with a pellet gun. The shooting was reportedly unprovoked and Keuhner was off duty at the time. Video of the dog's owner confronting Keuhner was uploaded online, and later gained national coverage. Keuhner resigned in June 2022 and was charged with a class A misdemeanor for animal abuse.

Library resolution In 2023, the county council issued a resolution aimed at library policies and staff online activities. The resolution followed protests and comments at council meetings from residents who complained about a staff member wearing gender non-conforming clothes. Within the resolution, the council asked the library CEO to remove an article they shared on their personal LinkedIn profile related to conservative campaigns targeting public libraries and freedom of speech.

Politics

Local The Republican Party predominantly controls politics at the local level in St. Charles County. Republicans hold all the elected positions in the county.

Position Incumbent Party Assessor Travis Welge Republican Collector Michelle McBride Republican Council Member – District 1 Matt Swanson Republican Council Member – District 2 Joseph Brazil Republican Council Member – District 3 Michael Elam Republican Council Member – District 4 David Hammond Republican Council Member – District 5 Terry Hollander Republican Council Member – District 6 Nancy Schneider Republican Council Member – District 7 Tim Baker Republican County Executive Steve Ehlmann Republican Director of Elections Kurt Bahr Republican Prosecuting Attorney Joe McCulloch Republican Recorder Mary Dempsey Republican Sheriff Scott Lewis Republican

State