[5] It was long recognized that St. Louis sits at the geographic center of Michigan's lower peninsula "as closely as can be determined."

A campaign by Clarence and Odessa Smazel in the early 1950s, owners of the St. Louis Leader-Press, a now-defunct local newspaper, resulted in the State of Michigan designating it as such: a sign in Clapp Park on Highway M-46 denotes the city as the official "Middle of the Mitten."

After the rebellious colonists' victory in the American Revolutionary War, the territory changed hands again, being ceded to the new United States.

In 1848 missionaries established the Bethany Lutheran Mission to serve local American Indians, mostly Anishinaabe-speaking Ojibwe (also known in the US as Chippewa).

Following a Native American path to the mission, the European-American Joseph W. Clapp came to the area in 1853, where he built the first house of present-day St. Louis.

[6] By the late nineteenth century, the discovery of mineral springs made St. Louis a destination for people seeking the health benefits of local mineral-rich water, which had the added feature of magnetizing steel.

Famous guests who credited the water with cures included detective Allan Pinkerton and Civil War general "Fighting Joe" Hooker.

St. Louis is the site of the former Michigan Chemical Corporation plant, which helped market and produce DDT as a widely commercial product.

The mixup occurred due what was described as a "triple witching hour" of events: a labor strike with management's replacing regular workers; a shortage of bags that helped distinguish between cattle feed additive and the flame-retardant PBB; and storing both the cattle feed and the fire retardant in the same dimly lit warehouse.

[9] Dredging has been underway for years to remove contaminants from the Pine River, which runs alongside the property where the plant was located.

[10][11][12] St. Louis has gained some jobs by inviting the State of Michigan to build a minimum-security prison between Union and Croswell Roads (Pine River Correctional Facility), on the former Reichard "Rainbow Trail" hatchery property.