Cities in St. Charles County, Missouri by Population (2024)

There are 21 cities in St. Charles County, Missouri.

Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)

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City
Rank
State
2024 Population
2020 Census
Annual Change
Density (mi²)
Area (mi²)
O'Fallon1Missouri95,69591,6311.07%3,13530.52
St. Charles2Missouri71,63070,7380.31%2,84225.20
St. Peters3Missouri59,34357,7030.7%2,64022.48
Wentzville4Missouri49,47744,9172.36%2,31721.36
Lake St. Louis5Missouri19,89116,7834.06%2,3298.54
Dardenne Prairie6Missouri14,35812,7702.84%2,6925.33
Cottleville7Missouri5,8795,6950.79%1,2424.73
Wright City8Missouri5,6184,8643.48%9276.06
Weldon Spring9Missouri5,2175,333-0.55%6827.65
St. Paul10Missouri4,0143,0606.33%5577.21
Marthasville11Missouri1,2991,2491.01%1,5210.85
Flint Hill12Missouri8628101.53%3072.81
Foristell13Missouri6435513.71%1066.08
Josephville14Missouri5425161.31%1902.85
New Melle15Missouri532540-0.38%3151.69
West Alton16Missouri347357-0.57%1228.81
Portage Des Sioux17Missouri323331-0.61%5620.57
Augusta18Missouri263269-0.38%2990.88
Defiance19Missouri94688.05%931.01
Weldon Spring Heights20Missouri9296-1.07%9580.10
Three Creeks21Missouri770%14.78

Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.

What is the largest city in St. Charles County, Missouri?

O'Fallon is the largest city in St. Charles County.

What is the smallest city in St. Charles County, Missouri?

Three Creeks is the smallest city in St. Charles County.

How many cities are in St. Charles County?

There are 21 cities in St. Charles County, Missouri.

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