The City of St. Charles is a charter city under the Missouri Constitution. The City Council is the governing body for the City of St. Charles.  The City Council consists of ten members one from each ward nominated and elected by the qualified registered voters of their respective wards. Each councilmember elected serves a three-year term.

There are ten City Council wards. Ward boundaries are established by ordinance following each decennial census and may be changed at other times. Wards are comprised of compact and contiguous territory and contain, as nearly as possible, an equal number of inhabitants Ward Map. 

The executive power in the City is vested in the Mayor who is recognized as the head of the City government for all legal and ceremonial purposes and by the Governor of Missouri for all purposes of military law.