O'Fallon Population

1870–2026

32,600

2026 projection

0.6% since 2020 (increase)

05K10K15K20K25K30K35K18801900192019401960198020002020

Source: U.S. Census Bureau decennial counts and annual estimates. 2026 is a projection. Values between recorded years are interpolated.

Use the left and right arrow keys to inspect population observations.

Population by year

Population estimates for O'Fallon. Annual change is shown as a percentage. Growth is the total change since the preceding observation.
202632,600-560.17%
202532,656+4701.46%
202432,186+70.02%
202332,179-620.19%
202232,241-1540.48%
202132,395-150.05%
202032,410+2,7899.42%
201929,621+190.06%
201829,602+2380.81%
201729,364+1650.57%

Showing 10 of 31 years.

O'Fallon Demographics

37.8median age

Median age

Female39.2 yrs
Male36 yrs

Adults

23,825
5,382 seniors · 23%18,443 other adults

Sex

Female 50.5% · 16,284Male 49.5% · 15,978

Population by age

MaleFemale85+ years, male: 27885+ years, female: 39380–84 years, male: 17080–84 years, female: 35375–79 years, male: 54775–79 years, female: 53270–74 years, male: 80270–74 years, female: 83765–69 years, male: 61265–69 years, female: 85860–64 years, male: 91760–64 years, female: 76255–59 years, male: 84555–59 years, female: 85750–54 years, male: 95950–54 years, female: 1,06845–49 years, male: 92745–49 years, female: 1,03640–44 years, male: 1,10040–44 years, female: 1,23735–39 years, male: 1,00635–39 years, female: 1,25830–34 years, male: 1,31630–34 years, female: 1,12125–29 years, male: 1,01425–29 years, female: 1,08520–24 years, male: 78820–24 years, female: 47115–19 years, male: 1,09215–19 years, female: 99810–14 years, male: 1,00110–14 years, female: 1,4815–9 years, male: 1,3695–9 years, female: 9820–4 years, male: 1,2350–4 years, female: 95585+80–8475–7970–7465–6960–6455–5950–5445–4940–4435–3930–3425–2920–2415–1910–145–90–45005001K1K

Hover or tap an age group to see exact counts. Use the up and down arrow keys to inspect age groups.

U.S. Census Bureau, 2024 ACS 5-year estimates · Table S0101

Race and ethnicity

Tap a square or a group below to highlight it.

Each square is about 1% of residents (roughly 323 people).

Hispanic or Latino residents can be of any race. All other groups exclude Hispanic residents.

U.S. Census Bureau, 2024 ACS 5-year estimates · Table B03002

O'Fallon Income

$105,982median household income

Median household income

$105,982

Half of households earn more, half earn less

Median earnings

$62,313

Typical yearly pay for a worker 25 or older.

Poverty rate

6.2%

About 1 in 16 residents

U.S. Census Bureau, 2024 ACS 5-year estimates · Tables S1901, S1501, S1701

O'Fallon Marital Status

59% of residents age 15 and older are married.

MarriedNever married
Overall
Male
Female
Marital status of residents age 15 and older
StatusOverallMaleFemale
Married59%59%58%
Never married27%30%23%
Divorced8%8%8%
Widowed5%2%8%
Separated2%1%3%

U.S. Census Bureau, 2024 ACS 5-year estimates · Table S1201

Sources

10 sources, all from the U.S. Census Bureau

Population

American Community Survey, 2024 5-year