St. Louis County is included in the Duluth, MN–Superior, WI Metropolitan Statistical Area.

Open pit mining of taconite and processing it into high grade iron ore remains an important part of the economy of the Iron Range and is directly tied to shipping in the twin ports of Duluth and Superior.

Parts of the federally recognized Bois Forte and Fond du Lac Indian reservations are in the county.

This area was long inhabited by Algonquian-speaking tribes: the Ojibwe (Chippewa), Ottawa and Potawatomi peoples were loosely affiliated in the Council of Three Fires.

Voyageurs National Park, established in 1975, is located in its northwestern corner, on the south shore of Rainy Lake on the Canada–US border; it is popular with water enthusiasts and fishers.

[5] Duluth on Lake Superior is one of the most important fresh-water ports in the United States.

The county has a humid continental climate (Köppen Dfb), slightly moderated by its proximity to Lake Superior.

Winters are long, snowy, and very cold, normally seeing maximum temperatures remaining below 32 °F (0 °C) on 106 days.

Due to global warming, in January 2019 Tracy Twine, professor at the University of Minnesota's Department of Soil, Water and Climate, said "we just don't expect temperatures to be below 10 degrees Fahrenheit in Duluth anymore.

According to the 2010–2015 American Community Survey, the ancestral makeup was 24.3% German, 15.9% Norwegian, 13.0% Swedish, and 10.2% Irish.

Since 1992, the only time when a Republican obtained more than 34% of the vote was in the elections of 1994 (the year of the Republican Revolution) when the incumbent Independent-Republican governor won the statewide vote by a landslide of more than 60%, and when the Independent-Republican senatorial candidate won election with 49% statewide, both of which are rare occurrences in Minnesota.

St. Louis County has long been one of the strongest Democratic bastions in the state outside of the Twin Cities.

In 2020, Trump became the first Republican since Herbert Hoover to get more than 40% of the vote in St. Louis County, but Joe Biden bolstered the Democratic margin of victory from 11.7% to 15.6%.

Two years later Cravaack was defeated by Democrat Rick Nolan, who represented the district until his retirement in 2019.

Republican St. Louis County commissioner Pete Stauber succeeded Nolan in one of three Democrat-to-Republican district flips in 2018, two of which happened in Minnesota.