O Fallon, Illinois.
Typical home $314,564 (+2.6% in a year), asking rent $1,631 (+6.6%). St. Louis, MO-IL metro.
to buy the typical home at today's mortgage rate — +$889 (+117%) since Jan 2020.
- 1 year
- Up $7,984 +3%
- $306,580$314,564 since Sep 2025
- 5 years
- Up $63,271 +25%
- $251,293$314,564 since Sep 2021
Monthly payment to buy the typical home
Home value × that month's 30-year mortgage rate, 20% down, principal and interest. This is the line households feel: prices and rates compound each other.
- O Fallon$1,651
- Illinois$1,553
- United States$1,922
At the last five years' pace, a typical home here doubles in price every 15 years.
Typical home values in O Fallon, IL rose 2.6% over the past year — faster than the nation's +1.2%.
Asking rents in O Fallon, IL rose 6.6% over the past year — faster than the nation's +2.7%.
Owning the typical home in O Fallon runs $890/mo more than renting one. The gap peaked at $969 in Oct 2023.
That is $2,521 a month against $1,631 rent: a $1,651 mortgage payment, plus $533 property tax and $337 insurance & upkeep.
Owning vs renting — O Fallon
The owning line is the typical home's monthly payment at that month's rate, plus property tax and insurance & upkeep; the renting line is the typical asking rent; the grey line is the mortgage payment on its own. Same homes, same months, both ways of paying for a roof.
- Owning all in$2,521
- Renting$1,631
- Mortgage only$1,651
Property tax · $533/mo 2.03% of value a year — the ACS 2020-2024 median bill over the median home value for Saint Clair County, IL
Insurance & upkeep · $337/mo insurance, maintenance and repairs together, from the BLS Consumer Expenditure Survey — the national figure for mortgaged homeowners, scaled to this market's home value. BLS publishes the three bundled and they cannot be split.
Both are priced off the same month's home value, so they rise with the market. Neither is a quote — a specific home's bill depends on its assessment, its age and its insurer.
Living in O Fallon, St. Clair County, Illinois
O Fallon is a city of 32,289 people in St. Clair County. Half its households earn more than $105,982 a year and half less, against $73,854 across St. Clair County; 6% of its people live below the poverty line. 70% of its homes are lived in by their owners and 30% are rented. Unemployment in O Fallon was 3.2% in August 2026, and St. Clair County had 0.9% fewer jobs in 2025 than the year before. The most residents work in schools and health care, then professional services.
Written by AI Claude Sonnet 5.5 wrote this on 23 October 2026 from the figures here, a list of nearby places and what it knows. It can be wrong or out of date.
What it’s like
The place. O Fallon is a city in St. Clair County, Illinois, with a population that has grown past the size of a small town. Household incomes run well above the county's, and fewer residents live below the poverty line than you might expect. Most homes are lived in by their owners, and a majority of adults hold a four-year degree. Winters are cold, with some snow, and summers get hot, with a fair amount of rain through the year.
Work. Many residents work in schools, hospitals and social care, with others in professional and business services, government and shops. Among the largest workplaces in O Fallon are St. Elizabeth Hospital, the O Fallon CCSD 90 Schools and the O Fallon Township High School District. Unemployment is lower than it was a year earlier, though across St. Clair County there were slightly fewer jobs last year than the year before. A good number of residents work from home, and the typical commute is a moderate one.
Things to do. Cahokia, an archaeological site, is a short drive away. A longer drive brings you to Gateway Arch National Park, along with the Saint Louis Zoo and Forest Park, where the zoo and a wide stretch of gardens and open ground sit side by side.
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- 12,816households
- 52%of adults have a degree
- 6%below the poverty line
- 25 mintypical commute
- 20%work from home
What residents work in
Employed residents by industry, from the Census survey. St. Clair County had 89,192 jobs in 2025, 0.9% fewer than the year before (Bureau of Labor Statistics).
Weather through the year
Coldest in January, with highs near 43° and lows near 24°; warmest in July, with highs near 90° and lows near 68°. About 11 inches of snow and 43 inches of rain and melted snow a year.
Average daily high and low, 1991–2020, at the Belleville Siu Rsch weather station, 7 miles away (NOAA).
Largest workplaces in O Fallon
- St. Elizabeth HospitalGeneral hospital878FTE
- O Fallon CCSD 90School district683FTE
- O Fallon Twp HSD 203School district471FTE
- WalmartWarehouse clubs and supercenters384
- Stake Center Locating - O'FallonAll other support services376
- Sam's ClubWarehouse clubs and supercenters199
- Menards"home centers"161
- Schnuck MarketsSupermarket groc not convenience store122
Staff on average in 2025, as each workplace reported it to OSHA with its injury records: 22 workplaces with 20 or more staff, 3,731 people in all. Hospitals come from their Medicare cost reports (CMS, 2023) and school districts from the Common Core of Data (NCES, 2023–24); FTE marks full-time equivalent staff. Not listed: many offices and banks, which need not report to OSHA; military bases, whose staff OPM withholds; and, in about half the states, city and county governments.
Natural hazards
- Heat wavesRelatively high
- HailRelatively high
- Cold wavesRelatively high
- EarthquakesRelatively high
- LightningRelatively high
- TornadoesRelatively high
FEMA’s National Risk Index (December 2025) rates the risk each natural hazard poses to the people, buildings and farms in O Fallon’s census tracts, against the rest of the country; all of them together, relatively high. It is meant for planning, not a substitute for a local risk assessment or a flood map: FEMA’s index.
From the U.S. Census Bureau’s 2020 census and its American Community Survey (2020–2024 five-year estimates), and the Bureau of Labor Statistics. A survey, so each figure has a margin of error, and figures it is not sure of are left out. More on St. Clair County and the St. Louis, MO-IL metro.
O Fallon home values
Zillow measures a city over its municipal boundary. Against the state and national figures, mid-tier homes, smoothed and seasonally adjusted.
- O Fallon$314,564
- Illinois$295,943
- United States$366,157
Sellers are cutting prices on about 1 in 3 O Fallon listings, and the typical home goes pending in 7 days — the market is roughly in balance.
When this market ran hot
Each cell is that month's year-on-year home-value growth. Read left to right, top row is the latest year — the 2021–22 band is the boom.
Market heat, inside the city limits
Share of listings with a price cut
The early-warning dial: sellers cut when buyers stop reaching. Rising cuts cool a market months before prices notice.
- O Fallon33.54%
- United States26.90%
Days to pending
How long the typical listing takes to go under contract.
- O Fallon7
- United States27
Homes for sale
Active for-sale inventory. More supply hands power to buyers.
- O Fallon107
New listings per month
Sellers arriving at the market.
- O Fallon43
Median sale price
What buyers actually paid — closed sales, not asking prices.
- O Fallon$347,704
- United States$371,407
Sale-to-list ratio
Above 100%, homes sell over asking; below, buyers negotiate wins.
- O Fallon99.64%
Zip codes with a O Fallon address
A different geography, not a breakdown. The figure above covers the municipality; these zips cover everywhere the Post Office calls O Fallon — often including townships beyond the city limits. Both come straight from Zillow, and they are not expected to average out.