St. Clair County, IL Demographics

The total population of St. Clair County is estimated to be 256,791 with 124,864 males (48.62%) and 131,927 females (51.38%). There are 7,063 more females than males in St. Clair County.
The median household income in St. Clair County was $68,116 in 2021, which marked an an increase of 2,991(4.59%) from $65,125 in 2020. This income is 91.30% of the U.S. median household income of $74,606 (all incomes in 2022 inflation-adjusted dollars).
Per the latest American Community Survey by the Census Bureau, St. Clair County sees its highest median household income among householders in the age group of 45 to 64 years old, at $75,916. Overall, the median household income for the county of St. Clair County stands at $67,395.
In St. Clair County, the median income for all workers aged 15 years and older, regardless of work hours, was $48,479 for males and $28,618 for females. However, when specifically considering full-time, year-round workers within the same age group, the median income was $67,459 for males and $48,656 for females.
In St. Clair County, the demographic landscape is diverse, spanning 6 distinct racial categories among households. Among these, Some Other Race households have the highest median household income at $101,051, while Black or African American households represent the opposite end with the lowest median household income of $48,800.
In 2022, the population of St. Clair County was 252,671, a 0.92% decrease year-by-year from 2021. Previously, in 2021, St. Clair County's population was 255,022, a decline of 0.70% compared to a population of 256,823 in 2020.
The median age in St. Clair County, IL is 39.2, as per 2021 ACS 5-Year Estimates. Of the total population, 19.58% were under the age of 15, 18.63% aged 15 to 29, 45.91% aged 30 to 64, 13.94% aged 65 to 84, and 1.94% were 85 years of age and older.
Racial distribution of St. Clair County population: 62.61% are White, 29.18% are Black or African American, 0.14% are American Indian and Alaska Native, 1.47% are Asian, 0.04% are Native Hawaiian and other Pacific Islander, 1.51% are some other race and 5.05% are multiracial.