St. Charles County

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. 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.

• County — St. Charles County • State — Missouri • Founded — October 1, 1812 • Seat Wl — St. Charles • Largest City Wl — O'Fallon • Leader Title — County executive • Leader Name — Steve Ehlmann (R) • Area Total Sq Mi — 593 • Area Land Sq Mi — 560 • Area Water Sq Mi — 32 • Area Water Percent — 5.4 • Population As Of — 2020 • Population Total — 405262 • Pop Est As Of — 2025 • Population Est — 426499 • Population Density Sq Mi — auto • Website — www.sccmo.org • District — 2nd • District2 — 3rd • Time Zone — Central • Named For — Charles Borromeo

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.

• Illustration — St. Charles County is the only known habitat of the threatened decurrent false aster in Missouri. According to the U.S. Census Bureau, the county has a total area of 593 sqmi, of which 560 sqmi is land and 32 sqmi (5.4%) is water. The highest elevation is 901 feet northwest of Augusta near Femme Osage Creek headwaters.

• 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)

• 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.

• Two Rivers National Wildlife Refuge (part)

• Saint Charles County

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 643 PD/sqmi. 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%.

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.

School districts include: • 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

• 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)

• Lindenwood University – St. Charles • St. Charles Community College – Cottleville

• St. Charles City-County Library District

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.

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.

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.

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

Past Gubernatorial Elections Results • Year — Republican — Democratic — Third Parties • 2024 — 59.51% 132,563 — 38.44% 85,628 — 2.05% 4,561 • 2020 — 58.12% 128,230 — 39.84% 87,888 — 2.04% 4,496 • 2016 — 54.52% 103,946 — 42.58% 85,704 — 2.90% 5,836 • 2012 — 48.58% 89,144 — 48.97% 89,860 — 2.45% 4,486 • 2008 — 44.51% 82,440 — 53.84% 99,705 — 1.65% 3,058 • 2004 — 55.90% 91,323 — 42.96% 70,184 — 1.14% 1,865 • 2000 — 58.24% 74,357 — 39.49% 50,415 — 2.27% 2,907 • 1996 — 49.48% 47,886 — 48.01% 46,462 — 2.50% 2,424 St. Charles County is divided among eleven legislative districts in the Missouri State House of Representatives, all of which are held by Republicans. • District 63 – Tricia Byrnes (R-Wentzville, since 2023). Consists of most of Wentzville. • District 64 – Deanna Self (R-St. Paul, since 2025). Consists of Flint Hill, Josephville, St. Paul, and parts of Foristell, O'Fallon, and Wentzville. • District 65 – Wendy Hausman (R-St. Peters, since 2023). Consists of West Alton, Portage Des Sioux, and parts of Cottleville, St. Charles, and St. Peters. • District 69 – Scott Miller (R-St. Charles, since 2025). Consists of parts of St. Peters and Weldon Spring. • District 102 – Richard West (R-Wentzville, since 2021). Consists of Augusta, Defiance, New Melle, Weldon Springs Heights, and parts of Cottleville, O'Fallon, St. Peters, and Weldon Spring. • District 103 – Dave Hinman (R-O'Fallon, since 2023). Consists of part of O'Fallon. • District 104 – Terri Violet (R-St. Peters, since 2025). Consists of part of St. Charles and St. Peters. • District 105 – Colin Wellenkamp (R-St. Charles, since 2025). Consists of part of St. Charles. • District 106 – Travis Wilson (R-St. Charles, since 2023). Consists of part of St. Charles. • District 107 – Mark Matthiesen (R-O'Fallon, since 2023). Consists of parts of Dardenne Prairie and O'Fallon. • District 108 – Mike Costlow (R-Dardenne Prairie, since 2025). Consists of Lake St. Louis and parts of Dardenne Prairie and O'Fallon. St. Charles County is divided into three districts in the Missouri State Senate, each of which are represented by Republicans. • District 2 – Nick Schroer (R-Defiance, since 2023). Consists of the communities of Augusta, Cottleville, Dardenne Prairie, Defiance, Josephville, Lake St. Louis, New Melle, O'Fallon, St. Paul, Weldon Spring, and Weldon Spring Heights. • District 10 - Travis Fitzwater (R-New Bloomfield, since 2023). Consists of the communities of Flint Hill, Foristell, and Wentzville. • District 23 – Adam Schnelting (R-St. Charles, since 2025). Consists of Portage Des Sioux, St. Charles, St. Peters, and West Alton.

Missouri is represented in the U.S. Senate by Josh Hawley and Eric Schmitt, whose most recent election results from the county are included here. Part of St. Charles County is included in Missouri's 2nd Congressional District and is currently represented by Ann Wagner in the U.S. House of Representatives. Most of St. Charles County is included in Missouri's 3rd Congressional District and is currently represented by Bob Onder (R-Lake St. Louis) in the U.S. House of Representatives.

St. Charles County has long been a Republican stronghold despite being an urban county, likely due to it being the wealthiest county in Missouri. Despite this, it did vote for Medicaid expansion in 2020, legal recreational marijuana in 2022, and legal abortion in 2024. It was also one of the few counties in Missouri to shift towards the Democrats from 2020 to 2024.

Republican Donald Trump won the most votes in St. Charles County, with 41.50 percent. U.S. Senator Ted Cruz (R-Texas) came in second with 38.87 percent, Governor John Kasich (R-Ohio) placed third with 10.70 percent, and U.S. Senator Marco Rubio (R-Florida) was fourth with 7.10 percent. Democratic U.S. Senator Bernie Sanders (I-Vermont) won the primary with 54.32 percent to former Secretary of State Hillary Clinton's 44.80 percent.

Republican Former U.S. Senator Rick Santorum (R-Pennsylvania) won the most votes in St. Charles County, with 56.29 percent. Former Governor Mitt Romney (R-Massachusetts) came in second with 25.43 percent, and former U.S. Representative Ron Paul (R-Texas) was third with 12.69 percent. Democratic With incumbent President Barack Obama facing no serious opposition, few St. Charles County voters voted in the Democratic primary; Obama won 87.83 percent.

Republican Former Governor Mitt Romney (R-Massachusetts) won the most votes in St. Charles County, with 37.72 percent. U.S. Senator John McCain (R-Arizona) came in second with 34.95 percent, former Governor Mike Huckabee (R-Arkansas) placed third with 21.83 percent, and U.S. Representative Ron Paul (R-Texas) was fourth with 3.83 percent. Democratic Former U.S. Senator Hillary Clinton (D-New York) received a total of 23,611 votes, more than any candidate from either party in St. Charles County during the 2008 presidential primary.

• Josephville • Weldon Spring Heights

• Defiance

• Apple Island • Dresser Island • Ellis Island • Howell Island • Two Branch Island

Westplex is an area within St. Charles County in east-central Missouri to the west of St. Louis County. The Westplex is part of St. Charles County that used to be called "The Golden Triangle". The "triangle" was formed by I-70 to the north, Missouri Route 94 to the southeast, and I-64 to the southwest. Since almost all of the growth in St. Charles County was within this triangle it was dubbed the "Golden" area of St. Charles County, hence, Golden Triangle. Today the Westplex is made up of St. Charles, St. Peters, Weldon Spring, Cottleville, Dardenne Prairie, O'Fallon, Lake St. Louis, and Wentzville.