• county
  • FIPS 29183
  • Largest town: O'Fallon

St. Charles County, Missouri

St. Charles County had 423,726 residents in the Census Vintage 2024 estimate, on 560.5 square miles of land. It ranks 3rd of 115 in Missouri by population and 65th by land area.

Population
423,726
#3 of 115 in Missouri · #180 in US
Area
560.5 sq mi
#65 of 115 in Missouri · #1,848 in US
Density
756 / sq mi
#4 of 115 in Missouri · #202 in US
Median household income
$98,765
#1 of 115 in Missouri · #151 in US

Census Vintage 2024 estimates · SAIPE 2023 income · 2024 Gazetteer land area

St. Charles County within Missouri. Pin: Jefferson City.

Measure from here

Tools and pages that start from St. Charles County

St. Charles County population, land area and income

St. Charles County had 423,726 residents in the Census Vintage 2024 estimate, on 560.5 square miles of land. It ranks 3rd of 115 in Missouri by population and 65th by land area. That works out to 756.0 people per square mile, 7.9 times the US average of 96.3, and in the top tenth nationally.

The median county-equivalent in Missouri has 19,100 residents, so St. Charles County is 22.2 times that size.

Its SAIPE 2023 median household income of $98,765 is in the top tenth among 3,143 counties with an estimate.

National rank among 3,144

Population

423,726

3144th1st

180th of 3,144 (US)

Land area

561 sq mi

3144th1st

1848th of 3,144 (US)

Density

756.0 / sq mi

3144th1st

202nd of 3,144 (US)

Median household income

$98,765

3143rd1st

151st of 3,143 (US)

Rank within Missouri (115)

Population

423,726

115th1st

3rd of 115 (MO)

Land area

561 sq mi

115th1st

65th of 115 (MO)

Density

756.0 / sq mi

115th1st

4th of 115 (MO)

Median household income

$98,765

115th1st

1st of 115 (MO)

How St. Charles County's population changed since 2020

St. Charles County gained 17,303 residents between the July 2020 and July 2024 estimates, a rise of 4.3%. That ranks 22nd of 115 in Missouri for growth. The median Missouri county changed by +1.4%, and the state as a whole by +1.5%.

Since the April 2020 estimates base, St. Charles County recorded 17,428 births and 15,070 deaths, a natural change of +2,358. Net international migration added +4,904 and net domestic migration, people moving to or from other US counties, came to +11,324. The largest single component was domestic migration, which added 11,324 people.

406.4k2020410.5k2021414.1k2022418.0k2023423.7k2024
Census Vintage 2024 county estimates for July 1 of each year. The axis starts above zero so year-to-year changes are visible.

Components of change, April 2020 to July 2024

Births
17,428
Deaths
15,070
Net international migration
+4,904
Net domestic migration
+11,324
Change, July 2023 to July 2024
+5,768

Where St. Charles County is

The Census internal point of St. Charles County is at 38.781100, -90.674900. It sits in UTM zone 15N. The map shades Missouri's 115 county-equivalents by population change from 2020 to 2024, darker for faster growth, with St. Charles County outlined. Dots are towns of 1,000+ people with residents in it.

Pettis County: +1.8%Henry County: +2.7%Texas County: +5.7%Madison County: +1.8%St. Louis city: -6.9%Cole County: +1.3%Washington County: +0.6%Macon County: -0.1%Barton County: +0.8%Grundy County: +0.1%Cedar County: +5.7%Randolph County: -1.6%Ray County: +0.3%Caldwell County: +2.0%Benton County: +6.1%Douglas County: +5.9%Shannon County: +3.4%Dade County: +0.5%Wright County: +7.1%Gentry County: +2.6%Lawrence County: +3.0%Cooper County: +2.9%Hickory County: +5.6%Moniteau County: +0.5%Dent County: +2.3%Monroe County: +2.3%Maries County: +0.7%Bollinger County: +0.5%Clinton County: +2.4%Knox County: +0.0%Webster County: +7.8%Harrison County: +0.4%Pulaski County: -0.1%Adair County: +1.5%Warren County: +7.7%Daviess County: +1.3%Audrain County: -1.9%Howard County: -0.1%Linn County: +0.4%Saline County: -0.1%Miller County: +3.6%Dallas County: +4.3%Morgan County: +6.7%New Madrid County: -6.8%Newton County: +4.8%Oregon County: +1.0%Franklin County: +2.3%Greene County: +2.9%Ralls County: +1.4%Lafayette County: +1.4%Livingston County: +4.8%McDonald County: +3.3%Barry County: +3.1%Cape Girardeau County: +2.2%Carroll County: -0.6%Christian County: +7.6%Vernon County: +0.6%Carter County: +3.0%Andrew County: -0.1%Jasper County: +2.9%Worth County: -4.9%Lincoln County: +10.1%Marion County: -0.2%Holt County: +1.2%Howell County: +2.4%St. Francois County: +1.6%Chariton County: +0.1%Butler County: -0.6%Iron County: -1.0%Perry County: +0.7%Cass County: +5.3%St. Louis County: -1.0%Dunklin County: -4.3%Wayne County: -1.1%Ozark County: +6.7%Laclede County: +1.9%Reynolds County: -2.5%Lewis County: -1.9%Taney County: +1.2%Ripley County: +0.4%Ste. Genevieve County: +0.4%Scotland County: -0.1%Putnam County: -3.1%Schuyler County: +1.5%Shelby County: -2.8%Boone County: +4.4%Mercer County: -1.7%Platte County: +5.6%Camden County: +3.1%Bates County: +2.1%Johnson County: +3.4%Sullivan County: -3.8%Atchison County: -3.1%Scott County: -0.2%Montgomery County: +2.0%Jefferson County: +2.2%Clark County: -0.5%Callaway County: +1.8%St. Clair County: +5.4%Buchanan County: -1.1%Pemiscot County: -7.6%Polk County: +4.6%Phelps County: +2.5%Stone County: +4.6%Osage County: +1.7%Clay County: +3.6%Nodaway County: -2.4%Crawford County: -1.0%Jackson County: +1.4%St. Charles County: +4.3%Mississippi County: -3.1%Pike County: +3.1%Stoddard County: -0.7%Gasconade County: -0.7%DeKalb County: -14.8%
Change 2020 to 2024
  1. < -0.7%
  2. < +0.5%
  3. < +2.0%
  4. < +3.6%
  5. ≥ +3.6%
no data

Orange pin: St. Charles County internal point. Dark pin: Jefferson City.

Internal point

Decimal
38.781100, -90.674900
DMS
38°46'51.96"N 90°40'29.64"W
UTM
15N 701965.4E 4295053.0N
Geohash
9yzs8eus3
Plus code
86CFQ8JG+C2

Towns in St. Charles County

9 incorporated places of 1,000+ people have residents in St. Charles County, 326,831 people together, or 77% of the county. Each figure counts only the part of the town inside St. Charles County; towns marked "part" extend into another county. The largest is O'Fallon with 95,355.

  1. 01O'Fallon95,355
  2. 02St. Charles72,458
  3. 03St. Peters61,398
  4. 04Wentzville48,646
  5. 05Lake St. Louis19,160
  6. 06Dardenne Prairie14,407
  7. 07Cottleville6,378
  8. 08Weldon Spring5,304
  9. 09St. Paul3,725
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering St. Charles County

The Census 2024 county adjacency file lists 7 neighbors for St. Charles County, including 3 across a state line. The most populous is St. Louis County, MO, with 992,929 residents. Distances run between Census internal points in a straight line.

Distance to Jefferson City and the nearest big city

Jefferson City is 82.0 miles W of St. Charles County's internal point in a straight line. The nearest place of 100,000 or more is St. Louis, MO (population 279,695), 25.3 miles away. The nearest place of 10,000 or more is O'Fallon, MO (population 95,355), 2.5 miles away.

St. Charles County FIPS code

The FIPS code of St. Charles County is 29183: state code 29 for Missouri plus county code 183. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $98,765.

Questions people ask

What is the population of St. Charles County, Missouri?

The Census Vintage 2024 estimate for July 1, 2024 is 423,726. That is up 17,303 people (4.3%) from the July 2020 estimate of 406,423.

What is the FIPS code of St. Charles County?

29183. The first two digits (29) are Missouri; the last three (183) identify the county.

What is the largest town in St. Charles County?

O'Fallon, with 95,355 residents inside St. Charles County in 2024.

Which counties border St. Charles County?

7 county-equivalents border it in the Census 2024 adjacency file: St. Louis County, MO; Madison County, IL; Franklin County, MO; Lincoln County, MO; Warren County, MO; Jersey County, IL; Calhoun County, IL.

Sources and data as of

Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.

  1. 01Census Vintage 2024 county population estimates
  2. 02Census 2024 Gazetteer, counties
  3. 03Census SAIPE 2023 state and county estimates
  4. 04Census Vintage 2024 subcounty population estimates
  5. 05Census 2024 county adjacency file
  6. 06Census 2024 cartographic boundary file, counties (1:5,000,000)

How every number is computed: methodology. Spotted a wrong figure? Report an error.