Portage Des Sioux is a city in St. Charles County, Missouri, United States.

Zenon Trudeau and François Saucier in reaction to American plans to build a military post about twelve miles (19 km) downstream.

The Treaties of Portage des Sioux in 1815 were signed here ostensibly settling Native American and United States conflicts in the War of 1812.

These treaties were to ultimately result in the Black Hawk War and the tribes being forced to move west of Missouri.

Public education in Portage Des Sioux is administered by the Orchard Farm School District.