St. Clair County was the first county established in the state of Illinois. It was created before the state of Illinois as it was one of two counties established in the Northwest Territory in 1790. The County was named for Arthur St. Clair, Governor of the Northwest Territory and Revolutionary War officer who organized the county in 1790. In its original boundaries, the county covered two-thirds of present-day Illinois. Greater St. Louis is the informal name of the St. Louis Metropolitan Statistical Area, which St. Clair County and is the largest in the state of Missouri.

Belleville is the county seat of St. Clair County. George Blair named the city in 1814, which means Beautiful City. Belleville’s downtown is home to blues, jazz, and rock clubs. Belleville Philharmonic Society was formed in 1866, making it the second oldest philharmonic orchestra in the country. Lebanon is a city in St. Clair County and like many other places in "Little Egypt" or Southern Illinois; Lebanon was named after the Middle Eastern country of the same name. Lebanon is home to McKendree College. Founded in 1828, McKendree College is the oldest college in Illinois.

Scott Air Force Base is located in St. Clair County, near Belleville. The government named the field after Corporal Frank S. Scott, the first enlisted person to be killed in an aviation crash. The base serves as the headquarters for the Air Mobility Command, the United States Transportation Command, the Eighteenth Air Force, and the Air Force Communications Agency. Its airfield is also used by MidAmerica St. Louis Airport. MidAmerica operates as a Joint Use Airport and is currently served by Allegiant Air. With more than 13,000 employees, Scott is one of the top five employers in the St. Louis region.

St. Clair County is surrounded by several major tourist attractions including the National Shrine of Our Lady of the Snows, Gateway International Raceway, Cahokia Mounds, Belleville Labor and Industry Museum, Cahokia Courthouse, Frank Holten State Park, Illinois Caverns State Natural Area, Jarrot Mansion, Emma Kunz House, Saint Peter's Cathedral and the Victorian Home Museum.

Welcome to the St. Clair County, Illinois website, your community on the Internet. Here you will find valuable information about Cecil County including coupons, restaurants, shopping, hotels, local businesses, parks, recreation, government, history, transportation, real estate, public services, dining, arts and entertainment, spas, salons, schools, sports, automotive, banking, shops, healthcare, relocation, travel, tourism, and vacations in St. Clair County, O'Fallon, Saint Libory, Alorton, Belleville, Brooklyn, Lovejoy, Cahokia, Caseyville, Centreville, Dupo, East Carondelet, East St. Louis, Fairview Heights, Fayetteville, Freeburg, Lebanon, Lenzburg, Marissa, Mascoutah, Millstadt, New Athens, Sauget, Shiloh, Smithton, St. Libory, Summerfield, Swansea, Washington Park, East St. Louis, Engelmann, Prairie du Long, Shiloh Valley, St. Clair, Stites, Stookey and Sugarloaf.
Places of interest in St. Clair County include Cahokia Mounds, Saint Louis University, Lindenwood University, Southwestern Illinois College, McKendree College, MidAmerica St. Louis Airport, Air Mobility Command, United States Transportation Command, Eighteenth Air Force, Air Force Communications Agency, Greater St. Louis, National Stock Yards, Scott AFB, Scott Air Force Base, Peabody River King St. Fish and Wildlife Area, Church of the Holy Family, National Shrine of Our Lady of the Snow, GMC Stadium, Cahokia Courthouse, Frank Holten State Park, Gateway International Raceway, Bellefontaine House, Belleville Labor and Industry Museum, Broadway Center of Arts, Illinois Caverns State Natural Area, Jarrot Mansion, Emma Kunz House, Martin-Boismenue House, Peterstown House, Saint Peter's Cathedral, William and Florence Schmidt Art Center and the Victorian Home Museum.