St. Clair County Demographics

A map of St. Clair County's Population by Race

St. Clair County, Illinois had a population of 257,400 in 2020. It was 58.5% White, 29.5% Black, 1.4% Asian, 4.9% Hispanic, 0.7% Native American/Other, and 5.0% Multiracial. This map presents the population of St. Clair County, with one dot drawn for each person counted in the 2020 Census, color-coded by race.

St. Clair County is the 9th most populous county of the 102 counties in Illinois.

St. Clair County's White Population

150,496 residents of St. Clair County identify as White, or 58.5%. This makes the White share of the population of St. Clair County roughly similar to the White share of the population of Illinois (58.3% White). Of the 102 counties in Illinois, St. Clair County is ranked #99 in terms of White residents as a share of the population.

St. Clair County is more White than neighboring St. Louis County (42.9% White). St. Clair County is less White than neighboring Monroe County (93.5% White), Madison County (80.4% White), Randolph County (84.4% White), and Clinton County (89% White).

St. Clair County's Black Population

76,013 residents of St. Clair County identify as Black, or 29.5%. This makes the Black share of the population of St. Clair County larger than the Black share of the population of Illinois (13.9% Black). Of the 102 counties in Illinois, St. Clair County is ranked #2 in terms of Black residents as a share of the population.

St. Clair County is more Black than neighboring Monroe County (0.3% Black), Madison County (9.3% Black), Randolph County (7.9% Black), and Clinton County (3.1% Black). St. Clair County is less Black than neighboring St. Louis County (42.8% Black).

St. Clair County's Asian Population

3,623 residents of St. Clair County identify as Asian, or 1.4%. This makes the Asian share of the population of St. Clair County roughly similar to the Asian share of the population of Illinois (5.8% Asian). Of the 102 counties in Illinois, St. Clair County is ranked #20 in terms of Asian residents as a share of the population.

St. Clair County is more Asian than neighboring Monroe County (0.5% Asian), Madison County (1% Asian), Randolph County (0.3% Asian), and Clinton County (0.5% Asian). St. Clair County is less Asian than neighboring St. Louis County (4% Asian).

St. Clair County's Hispanic Population

12,582 residents of St. Clair County identify as Hispanic, or 4.9%. This makes the Hispanic share of the population of St. Clair County less than the Hispanic share of the population of Illinois (18.2% Hispanic). Of the 102 counties in Illinois, St. Clair County is ranked #34 in terms of Hispanic residents as a share of the population.

St. Clair County is more Hispanic than neighboring Monroe County (1.8% Hispanic), Madison County (4.1% Hispanic), Randolph County (3.4% Hispanic), and Clinton County (3.8% Hispanic). St. Clair County is less Hispanic than neighboring St. Louis County (5.1% Hispanic).

St. Clair County's Native American/Other Population

1,823 residents of St. Clair County identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other, or 0.7%. This makes the Native American/Other share of the population of St. Clair County roughly similar to the Native American/Other share of the population of Illinois (0.5% Native American/Other). Of the 102 counties in Illinois, St. Clair County is ranked #5 in terms of Native American/Other residents as a share of the population.

St. Clair County is more Native American/Other than neighboring Monroe County (0.3% Native American/Other), Madison County (0.6% Native American/Other), Randolph County (0.4% Native American/Other), and Clinton County (0.5% Native American/Other). St. Clair County is less Native American/Other than neighboring St. Louis County (0.8% Native American/Other).

St. Clair County's Multiracial Population

12,863 residents of St. Clair County identify as Multiracial, or 5.0%. This makes the Multiracial share of the population of St. Clair County roughly similar to the Multiracial share of the population of Illinois (3.2% Multiracial). Of the 102 counties in Illinois, St. Clair County is ranked #3 in terms of Multiracial residents as a share of the population.

St. Clair County is more Multiracial than neighboring Monroe County (3.5% Multiracial), St. Louis County (4.4% Multiracial), Madison County (4.7% Multiracial), Randolph County (3.6% Multiracial), and Clinton County (3.2% Multiracial).

Source: 2020 Census State Redistricting Data and Census TIGER/Line Shapefiles.