O'Fallon is a larger medium-sized city located in the state of Missouri. With a population of 93,663 people and 22 associated neighborhoods, O'Fallon is the seventh largest community in Missouri. There's nothing like the smell of a brand new house, and in O'Fallon, you'll find that a large proportion of houses were recently built. New growth in residential real estate is an indication that people are choosing to move to O'Fallon, and putting down their money on brand new construction. O'Fallon’s real estate is, on average, some of the newest in the nation. O'Fallon does seem to be experiencing an influx of affluent people, because the median household income is $104,863.00.

O'Fallon real estate is some of the most expensive in Missouri, although O'Fallon house values don't compare to the most expensive real estate in the U.S.

Also of interest is that O'Fallon has more people living here who work in computers and math than 95% of the places in the US.

One interesting thing about the economy is that relatively large numbers of people worked from their home: 13.95% of the workforce. While this number may seem small overall, as a fraction of the total workforce this is high compared to the rest of the county. These workers are often telecommuters who work in knowledge-based, white-collar professions. For example, Silicon Valley has large numbers of people who telecommute. Other at-home workers may be self-employed people who operate small businesses out of their homes.

O'Fallon is a good choice for families with children because of several factors. Many other families with children live here, making it a place where both parents and children are more likely to develop social ties with other families. The city’s good public school district and large population of college-educated adults provide an environment conducive to academic success. Many people own their own single-family homes, providing areas for children to play and stability in the community. Finally, O'Fallon’s overall crime rate is lower than average for the country.

O'Fallon is a decent-sized city, yet no one gets to work using public transit, because the city has no real transit system.

The citizens of O'Fallon are among the most well-educated in the nation: 42.41% of adults in O'Fallon have a bachelor's degree or even advanced degree, whereas the average US city has 21.84% holding at least a bachelor's degree.

The per capita income in O'Fallon in 2022 was $45,938, which is wealthy relative to Missouri and the nation. This equates to an annual income of $183,752 for a family of four.

O'Fallon is a somewhat ethnically-diverse city. The people who call O'Fallon home describe themselves as belonging to a variety of racial and ethnic groups. The greatest number of O'Fallon residents report their race to be White, followed by Black or African-American. Important ancestries of people in O'Fallon include German, Irish, English, Italian, and French.

The most common language spoken in O'Fallon is English. Other important languages spoken here include Spanish and Other Asian languages.