The Ojibwe (Chippewa), Ottawa, and Potawatomi peoples were loosely united in the Council of Three Fires and lived in this area for a long time. Native Americans were pushed to the outside of the territory as American immigrants arrived.
On February 20, 1855, the Minnesota Legislature formed Doty County, which was later renamed Newton County on March 3, 1855. The territory east and south of the St. Louis River was formerly part of the county, while the area east of the Vermilion River and north of the St. Louis River was part of Superior County. The county of Superior was renamed St. Louis County.
St. Louis County was renamed Lake County on March 1, 1856. Newton County was renamed St. Louis County, and that eastern portion was added to it; it was also expanded westward by incorporating sections of Itasca County, which comprised most of Carlton County at the time. St. Louis County was founded on May 23, 1857, when Carlton County was formed from sections of St. Louis and Pine counties.