O'Fallon, IL Demographics

A map of O'Fallon's Population by Race

O'Fallon, Illinois has an estimated population of 32,262, a less than 1% change from the 32,289 recorded in the 2020 Census. The population is 69.4% White, 16.5% Black, 5.8% Multiracial, 5.1% Hispanic, 2.6% Asian, and 0.5% Native American/Other. This demographic dot map shows the population of O'Fallon, with one dot drawn for each person counted by the Census, color-coded by race.

O'Fallon is about as racially diverse as it was in the 2020 Census. It is considerably less diverse than Illinois overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In O'Fallon, that probability was 48.8% in 2020 and 48.5% in the most recent ACS estimates.

O'Fallon is ranked the 58th most populous place in Illinois, out of 1,461 places. This ranking is based on the Census definition of a place, which includes incorporated places like cities, towns, and villages, as well as unincorporated census-designated places (CDPs). O'Fallon was ranked the 59th most populous place in the 2020 Census.

O'Fallon's White Population

22,382 residents of O'Fallon, or 69.4% of the population, identify as White. The share of White residents in O'Fallon is considerably higher than in Illinois overall, where 58.1% of the population is White. O'Fallon ranks 1241st statewide in terms of White residents as a share of the population, out of 1,461 places.

Since the 2020 Census, O'Fallon's White population has remained roughly the same. White residents' share of O'Fallon's population has remained roughly unchanged at 69.4%.

O'Fallon is more White than neighboring Shiloh (60.9% White), Scott AFB (63.6% White), Fairview Heights (51% White), and Lebanon (67.8% White). O'Fallon is less White than neighboring Swansea (70.1% White).

O'Fallon's Black Population

5,335 residents of O'Fallon, or 16.5% of the population, identify as Black. The share of Black residents in O'Fallon is slightly higher than in Illinois overall, where 13.3% of the population is Black. O'Fallon ranks 104th statewide in terms of Black residents as a share of the population, out of 1,461 places.

Since the 2020 Census, O'Fallon's Black population has grown by an estimated 2.6%. Black residents' share of O'Fallon's population has remained roughly unchanged at 16.5%.

O'Fallon is more Black than neighboring Scott AFB (11.2% Black). O'Fallon is less Black than neighboring Shiloh (24.4% Black), Swansea (19.2% Black), Fairview Heights (27.6% Black), and Lebanon (17.9% Black).

O'Fallon's Asian Population

833 residents of O'Fallon, or 2.6% of the population, identify as Asian. The share of Asian residents in O'Fallon is slightly lower than in Illinois overall, where 5.9% of the population is Asian. O'Fallon ranks 193rd statewide in terms of Asian residents as a share of the population, out of 1,461 places.

Since the 2020 Census, O'Fallon's Asian population has declined by an estimated 4.6%. Asian residents' share of O'Fallon's population has remained roughly unchanged at 2.6%.

O'Fallon is more Asian than neighboring Scott AFB (1.1% Asian), Swansea (2.4% Asian), and Lebanon (0.7% Asian). O'Fallon is less Asian than neighboring Shiloh (3.3% Asian), and Fairview Heights (4% Asian).

O'Fallon's Hispanic Population

1,661 residents of O'Fallon, or 5.1% of the population, identify as Hispanic. The share of Hispanic residents in O'Fallon is considerably lower than in Illinois overall, where 18.8% of the population is Hispanic. O'Fallon ranks 494th statewide in terms of Hispanic residents as a share of the population, out of 1,461 places.

Since the 2020 Census, O'Fallon's Hispanic population has grown by an estimated 2.0%. Hispanic residents' share of O'Fallon's population has remained roughly unchanged at 5.1%.

O'Fallon is more Hispanic than neighboring Shiloh (4.9% Hispanic), and Swansea (0.9% Hispanic). O'Fallon is less Hispanic than neighboring Scott AFB (15.6% Hispanic), Fairview Heights (6.9% Hispanic), and Lebanon (5.5% Hispanic).

O'Fallon's Native American/Other Population

170 residents of O'Fallon, or 0.5% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in O'Fallon is comparable to the share in Illinois overall, where 0.5% of the population is Native American/Other. O'Fallon ranks 268th statewide in terms of Native American/Other residents as a share of the population, out of 1,461 places.

Since the 2020 Census, O'Fallon's Native American/Other population has declined by an estimated 26.7%. Native American/Other residents' share of O'Fallon's population has remained roughly unchanged at 0.5%.

O'Fallon is more Native American/Other than neighboring Scott AFB (0% Native American/Other), Swansea (0% Native American/Other), and Lebanon (0.2% Native American/Other). O'Fallon is less Native American/Other than neighboring Shiloh (0.7% Native American/Other), and Fairview Heights (0.9% Native American/Other).

O'Fallon's Multiracial Population

1,881 residents of O'Fallon, or 5.8% of the population, identify as Multiracial. The share of Multiracial residents in O'Fallon is slightly higher than in Illinois overall, where 3.4% of the population is Multiracial. O'Fallon ranks 109th statewide in terms of Multiracial residents as a share of the population, out of 1,461 places.

Since the 2020 Census, O'Fallon's Multiracial population has declined by an estimated 6.5%. Multiracial residents' share of O'Fallon's population has remained roughly unchanged at 5.8%.

O'Fallon is less Multiracial than neighboring Shiloh (5.9% Multiracial), Scott AFB (8.5% Multiracial), Swansea (7.4% Multiracial), Fairview Heights (9.5% Multiracial), and Lebanon (7.9% Multiracial).

Sources: Most recent population estimates are from the 2020-2024 American Community Survey 5-Year Estimates. 2020 population counts and map data are from 2020 Census State Redistricting Data. Geographic data are from Census TIGER/Line Shapefiles.