Madison County is a county in the U.S. state of Illinois. It is a part of the Metro East in southern Illinois. According to the 2020 census, it had a population of 264,776, making it the eighth-most populous county in Illinois and the most populous in the southern portion of the state. The county seat is Edwardsville, and the largest city is Granite City.
Madison County is part of the Metro-East region of the St. Louis, MO-IL Metropolitan Statistical Area. The pre-Columbian city of Cahokia Mounds, a World Heritage Site, was located near Collinsville. Edwardsville is home to Southern Illinois University Edwardsville. 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. Godfrey, the village named for Captain Benjamin Godfrey, offers Lewis and Clark Community College formerly the Monticello Female Seminary.
History
Madison County was established on September 14, 1812. It was formed from parts of Randolph and St. Clair counties and named for President James Madison. 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.
In the late 19th century, Madison County became an industrial region, and in the 20th century was known first for Graniteware, and later for its steel mills, oil refineries, and other heavy industries. The county had a large working population, and the county and surrounding area was a center of strength for the Democratic Party.
Industrial restructuring cost many jobs and reduced the population. The county now is part of the eastern St. Louis metropolitan area (nicknamed "Metro East"), as is neighboring St. Clair County.
In 2009, the EPA issued an air pollution report that ranked Madison County as the county with the second-highest cancer risk in the country due to air pollution, second only to Los Angeles County, California.
Geography
According to the U.S. Census Bureau, the county has a total area of , of which is land and (3.4%) is water. Madison County is on the Mississippi River, while the other major body of water is Horseshoe Lake.
Climate and weather
In recent years, average temperatures in the county seat of Edwardsville have ranged from a low of in January to a high of in July, although a record low of was recorded in January 1977 and a record high of was recorded in July 2012. Average monthly precipitation ranged from in January to in May. Climate Zone 4A per the International Energy Conservation Code.
Adjacent counties and city
Bond County - east
Clinton County - southeast
Jersey County - northwest
Macoupin County - north
Montgomery County - northeast
St. Charles County, Missouri - northwest
St. Clair County - south
St. Louis, Missouri - west
St. Louis County, Missouri - west
Parks and Reserves
Chouteau Island
Gabaret Island
Horseshoe Lake State Park
Mosenthein Island
Transportation
Madison County Transit serves the county with 25 bus routes and of bike trails.
Major highways
I-55
I-70
I-255
I-270
US 40
US 67
IL 3
IL 4
IL 100
IL 162
IL 140
IL 160
IL 143
IL 157
IL 159
IL 111
IL 203
IL 255
IL 267
Demographics
According to the 2020 census, the racial makeup of the county was 81.4% white (80.4% white non-Hispanic), 9.4% black or African American, 1.0% Asian, 0.3% American Indian, 6.3% two or more races, and 1.5% some other race. Those of Hispanic or Latino origin made up 4.1% of the population.
According to the 2010 census, there were 269,282 people, 108,094 households, and 71,756 families residing in the county. The population density was . There were 117,106 housing units at an average density of . The racial makeup of the county was 88.2% white, 7.9% black or African American, 0.8% Asian, 0.2% American Indian, 0.9% from other races, and 1.8% from two or more races. Those of Hispanic or Latino origin made up 2.7% of the population. In terms of ancestry, 32.7% were German, 14.9% were Irish, 10.5% were English, 7.5% were American, and 5.7% were Italian.