Southwestern Illinois Demographics

Madison and St. Clair counties remain the second most populous region in the State of Illinois with a combined population of 539,338 in 2010, the most recent year for which confirmed demographic numbers were available at the time of publication. The two counties represent approximately 19 percent of the population of the total St. Louis Standard Metropolitan Statistical Area (SMSA). Median household income continues to rise for area residents, jumping 24.6 percent in the last decade. Per capita income is also on the rise, up 29 percent since 2000. Southwestern Illinois also continues to make gains in educational attainment. The percentage of individuals earning a high school diploma or higher has increased from 82.6 percent in 2000 to 88.4 percent in 2010, and the percentage earning a bachelor's degree or higher is 23.5 percent for 2010.

St. Louis Metropolitan Area Demographics
Additional information about the demographics of the St. Louis region can be found on the website for the St. Louis Regional Chamber.

St. Louis Metropolitan Area Demographics

Madison and St. Clair Counties by the Numbers

Total Population

2000

2010

Madison County

258,941

269,282

St. Clair County

256,082

270,056

Combined Total

515,023

539,338

Population by Age – Under 18

Madison County

64,437

61,127

St. Clair County

70,925

68,594

Combined Total

135,362

129,721

Population by Age – 65 Years and Over

Madison County

36,923

38,507

St. Clair County

33,709

33,757

Combined Total

70,632

72,264

Income Per Capita Income (dollars)

Madison County

$20,509

$26,127

St. Clair County

$18,932

$24,770

Combined Average

$19,721

$25,449

Median Household Income (dollars)

Madison County 

$41,541

$51,941

St. Clair County

$39,148

$48,562

Combined Average

$40,345

$50,252

Educational Attainment (age 25+) Percent High School Graduate or Higher

Madison County

84.3

89.4

St. Clair County

80.9

87.4

Combined Average

82.6

88.4

Percentage of Bachelor’s Degree or Higher

Madison County

19.2

23

St. Claire County

19.3

23.9

Combined Average

19.3

23.5

Source: U.S. Census Bureau