[2] Madison County is part of the Metro East region of Greater St. Louis.

The pre-Columbian city of Cahokia Mounds, a World Heritage Site, was located near Collinsville.

To the north, Alton is known for its abolitionist and American Civil War-era history.

It is also the home of the Southern Illinois University School of Dental Medicine.

It was formed from parts of Randolph and St. Clair counties and named for President James Madison.

[3] At the time of its formation, Madison County included all of the modern State of Illinois north of St. Louis, as well as all of Wisconsin, part of Minnesota, and Michigan's Upper Peninsula.

[4] Madison County is on the Mississippi River, while the other major body of water is Horseshoe Lake.

Trains on the Lincoln Service route travel between Chicago and St. Louis.

In 2016, Donald Trump carried the largest share of the vote for any Republican presidential candidate since 1972.