Fredericktown is a city in and the county seat of Madison County, Missouri, United States, in the northeastern foothills of the St. Francois Mountains. The population was 3,985 at the 2010 census. The city is surrounded on three sides (east, west, and south) by the easternmost parcel of the Mark Twain National Forest.
The Fredericktown Courthouse Square Historic District, Fredericktown Missouri Pacific Railroad Depot, Fredericktown United States Post Office, Madison County Courthouse, and St. Louis, Iron Mountain and Southern Railroad Depot are listed on the National Register of Historic Places.
The history of Fredericktown revolves around the history of lead mining. The earliest beginnings of Fredericktown occurred around 1715 when local Indians guided French explorers to the area which at that time was part of the Upper Louisiana in order to show them sources of lead which the French had hoped would also contain silver.
The French Governor of French Louisiana Sieur Antoine de la Mothe Cadillac, failed to find silver, but succeeded in recruiting other French investors in The Company of the West, organized in 1717, to exploit the mineral resources of Louisiana.
The earliest European settlement in the area near what is now Fredericktown was Mine La Motte, a small community about six miles (10 km) to the north. Mine La Motte was first settled by Europeans to mine a large vein of galena lead ore distributed in dolomite that reached the surface there. The need for a local source of lead for ammunition made Mine La Motte one of the earliest European settlements in the interior of the North American continent.