The population of 259,132 (U.S. Census 2002 est.) is an increase of 1.2% since the 2000 Census of 256,082. This is an inspiring reversal of a negative trend in the previous decade. Per capita income is still around $18,932, but St Clair County is home to both MidAmerica St. Louis Airport and Scott Air Force Base.

There are two four-year colleges in St Clair County. Southwestern Illinois College is a comprehensive educational institution committed to providing the best learning opportunities. They are considered the starting point for higher education, the bridge to developing career skills and the pathway to personal achievement. While Southwestern is the sixth largest community college in the state of Illinois, McKendree College is a leader among today’s educational institutions. Founded in 1828, the historically significant campus exemplifies a classic and caring tradition that is combined with a contemporary curriculum. Public schools break the county into twenty-eight distinct areas for St. Clair’s elementary, middle and high schools. Twenty-five private schools in the county include a variety of Montessori, Academy style and religious teaching institutions.

If you visit St Clair County during mid-summer, don’t miss the annual St. Clair County Fair in Belleville, IL. This traditional county fair is held each year during the second week of August. The exposition building is open until 10 pm each night and carnival rides are open until 11:30. The Beer Garden, steeped in German tradition, is a popular oasis, and bands play there nightly until midnight.

Of the many attractions in the St. Clair County area, the biggest drawing card is the Gateway International Raceway in Madison. Fans from all across America come to watch the world's leading racecar drivers compete in the NASCAR Busch and Craftsman Truck Series, as well as the NHRA Sears Craftsman Nationals. The Gateway complex includes a lighted, 1.25-mile oval and a championship drag racing facility

St. Clair County is home to many significant pieces of 18th and 19th century architecture. The most popular attractions are:

• St. Peter’s Cathedral, completed in 1866, is modeled after the Cathedral of Exeter, England.
• The Martin-Boismenue House provides a glimpse into the lifestyle of local villagers at the time of Lewis and Clark.
• Built in 1830, The Emma Kunz House is the oldest Greek Revival brick home in Illinois, and is completely furnished. This attraction is a major illustration of the hardships of early settlers.
• The Jarrot Mansion is a two-story brick house that dates to the early 19th century. The interior of the mansion is well preserved to the early 19th century period and is continually being refurbished. The Cahokia Historical Commission maintains it.
• Belleville Labor & Industry Museum chronicles the region’s contribution in the late 19th century and houses permanent and special exhibition galleries, as well as an educational center and archives