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. O'Fallon has seen a significant amount of newer housing growth in recent years. Quite often, new home construction is the result of new residents moving in who are middle class or wealthier, attracted by jobs, a healthy local economy, or other amenities as they leave nearby or far away areas for greener pastures. This seems to be the case in O'Fallon, where 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.

A relatively large number of people in O'Fallon telecommute to their jobs. Overall, about 13.95% of the workforce works from home. While this may seem like a small number, as a fraction of the total workforce it ranks among the highest in the country. 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.

The city of O'Fallon is a decent size, but despite this, it doesn't have a viable public transit system that people can use to get to work.

The education level of O'Fallon ranks among the highest in the nation. Of the 25-and-older adult population in O'Fallon, 42.41% have at least a bachelor's degree. The typical US community has just 21.84% of its adults holding a bachelor's degree or graduate 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.