Census tract · St. Charles County
Census Tract 3122.09, St. Charles County, Missouri
Census Tract 3122.09, GEOID 29183312209, in St. Charles County, Missouri, mostly within O'Fallon (56% of its census blocks). 5,590 residents in the ACS 2020-2024 5-year estimates (±771); the 2020 Census counted 4,489.
Residents, 2020-2024
5,590
±771 (90% margin)
2020 Census count: 4,489
Median household income
$165,417
±$2,562 (90% margin)
St. Charles County: $104,692
Median home value
$491,100
±$52,942 (90% margin)
St. Charles County: $320,800
Median gross rent
not published
St. Charles County: $1,370
Where is Census Tract 3122.09?
Census Tract 3122.09 is one of 85 census tracts in St. Charles County, Missouri. It covers 3.07 square miles of land, 1,464 residents per square mile in 2020. Its GEOID, 29183312209, names it uniquely (how tract numbers and GEOIDs work).
| Place | Share of the tract |
|---|---|
| O'Fallon | 56% |
| Lake St. Louis | 8% |
6 census tracts border Census Tract 3122.09: Tract 3111.53 ($107,841), Tract 3119.08 ($144,625), Tract 3122.06 ($142,484), Tract 3122.07 ($93,070), Tract 3122.08 ($142,841) and Tract 9800*. The figure in brackets is each tract's median household income; * a special land-use tract (water, a park or an institution) with few or no residents.
Whether a tract counts as low- or moderate-income for bank lending (the Community Reinvestment Act) is set by the FFIEC against its metro area's family income: look it up in the FFIEC census geocoder.
Source: 2024 Gazetteer and 2020 block assignment files, U.S. Census Bureau · Census reference files
How many people live in Census Tract 3122.09?
The 2020-2024 American Community Survey puts Census Tract 3122.09's population at 5,590 (±771) in 1,817 households; the 2020 Census counted 4,489 residents and 1,391 housing units.
| Measure | Tract 3122.09 | O'Fallon |
|---|---|---|
| Total population | 5,590 ±771 | 93,801 |
| Households | 1,817 ±290 | 35,471 |
| Average household size | 3.08 ±0.21 | 2.63 |
| Housing units | 1,830 ±294 | 36,206 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 Census P.L. 94-171 · Check it at data.census.gov
Who lives in Census Tract 3122.09?
The median resident of Census Tract 3122.09 is 36.9 years old; 32.6% are under 18 and 7.7% are 65 or older. The largest group is non-Hispanic white residents at 81.8%, then non-Hispanic Asian residents at 7.0%. 6.8% of residents were born outside the United States.
| Measure | Tract 3122.09 | O'Fallon |
|---|---|---|
| Median age | 36.9 ±3.6 | 38.4 |
| Under 18 years | 32.6% ±4.1 pts | 24.2% |
| 65 years and over | 7.7% ±1.7 pts | 14.5% |
| Hispanic or Latino (any race) | 5.2% ±3.4 pts | 5.5% |
| White alone, not Hispanic | 81.8% ±7.3 pts | 79.5% |
| Black or African American alone, not Hispanic | 1.5% ±1.1 pts | 5.2% |
| Asian alone, not Hispanic | 7.0% ±6.2 pts | 4.8% |
| American Indian and Alaska Native alone, not Hispanic | 0.2% ±0.2 pts | 0.1% |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±0.6 pts | 0.0% |
| Two or more races, not Hispanic | 4.0% ±2.2 pts | 4.3% |
| Some other race alone, not Hispanic | 0.4% ±0.6 pts | 0.5% |
| Born outside the United States | 6.8% ±3.5 pts | 6.3% |
| Speak a language other than English at home (age 5+) | 9.5% ±4.2 pts | 7.9% |
| Civilian veterans (age 18+) | 3.5% ±2.3 pts | 6.0% |
| With a disability | 7.0% ±2.6 pts | 10.6% |
| No health insurance coverage | 2.9% ±2.5 pts | 3.9% |
| High school graduate or higher (age 25+) | 98.9% ±1.3 pts | 95.4% |
| Bachelor's degree or higher (age 25+) | 62.8% ±5.0 pts | 43.3% |
| Graduate or professional degree (age 25+) | 21.7% ±5.9 pts | 15.6% |
| Lived in the same house a year earlier | 87.4% ±6.3 pts | 90.6% |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in Census Tract 3122.09 earn?
Half of the 1,817 households in Census Tract 3122.09 earn less than $165,417 a year (±$2,562), against $104,692 across St. Charles County: 2nd highest of the county's 84 tracts with a reliable estimate.
| Measure | Tract 3122.09 | O'Fallon |
|---|---|---|
| Median household income | $165,417 ±$2,562 | $110,443 |
| Mean household income | $202,836 ±$27,688 | $128,022 |
| Per capita income | $67,202 ±$8,456 | $49,304 |
| People below the poverty line | 2.0% ±1.5 pts | 5.4% |
| Children under 18 below the poverty line | 0.0% ±1.9 pts | 6.2% |
| Households receiving SNAP | 0.0% ±1.9 pts | 4.4% |
| Households with a computer | 99.4% ±1.0 pts | 97.4% |
| Households with a broadband subscription | 98.5% ±1.7 pts | 94.9% |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in Census Tract 3122.09?
Owners occupy 96.5% of Census Tract 3122.09's occupied homes and renters 3.5%. The median owner-occupied home is valued at $491,100 by its owner (±$52,942).
| Measure | Tract 3122.09 | O'Fallon |
|---|---|---|
| Median home value (owner-occupied) | $491,100 ±$52,942 | $326,200 |
| Renters paying 35% or more of income on rent | 100.0% ±100.0 pts | 36.0% |
| Median monthly owner costs, with a mortgage | $2,680 ±$288 | $1,899 |
| Owner-occupied homes | 96.5% ±2.8 pts | 81.0% |
| Renter-occupied homes | 3.5% ±2.8 pts | 19.0% |
| Housing units | 1,830 ±294 | 36,206 |
| Single-family detached homes | 100.0% ±1.9 pts | 75.2% |
| Mobile homes | 0.0% ±1.9 pts | 3.4% |
| Built 2020 or later | 16.0% ±6.2 pts | 3.7% |
| Built 2010 to 2019 | 49.6% ±11.4 pts | 15.8% |
| Built 1939 or earlier | 0.4% ±0.6 pts | 0.8% |
| Households with no vehicle | 1.9% ±1.8 pts | 4.7% |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How do people in Census Tract 3122.09 get to work?
67.1% of Census Tract 3122.09's workers drive alone and 28.8% work from home. The average trip to work takes 26.3 minutes.
| Measure | Tract 3122.09 | O'Fallon |
|---|---|---|
| In the labor force (age 16+) | 82.7% ±4.5 pts | 73.1% |
| Unemployment rate | 1.6% ±2.3 pts | 2.7% |
| Drove alone to work | 67.1% ±10.6 pts | 75.2% |
| Carpooled | 2.0% ±2.4 pts | 4.3% |
| Public transportation | 0.0% ±1.1 pts | 0.1% |
| Walked | 0.0% ±1.1 pts | 0.8% |
| Worked from home | 28.8% ±11.5 pts | 18.1% |
| Mean travel time to work | 26.3 min ±2.0 | 25.5 min |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
How does Census Tract 3122.09 compare with the other tracts in St. Charles County?
Among St. Charles County's tracts with a reliable estimate, Census Tract 3122.09 ranks as shown below (1 = highest).
| Measure | In St. Charles County | In O'Fallon |
|---|---|---|
| Population | 27th of 84 | 9th of 22 |
| Residents per square mile | 70th of 85 | 21st of 23 |
| Median household income | 2nd of 84 | 1st of 22 |
| Per capita income | 7th of 84 | 1st of 22 |
| Median home value | 3rd of 84 | 1st of 22 |
| Bachelor's degree or higher | 2nd of 84 | 1st of 22 |
| Median age | 65th of 84 | 18th of 22 |
| Owner-occupied share | 6th of 84 | 2nd of 22 |
The tracts next to it on St. Charles County's income ladder
| Tract | Rank | Median household income |
|---|---|---|
| Tract 3111.03 | 1st | $170,625±$18,319 · within the margin of this tract |
| Tract 3122.09 | 2nd | $165,417±$2,562 |
| Tract 3120.01 | 3rd | $160,368±$20,698 · within the margin of this tract |
| Tract 3119.09 | 4th | $155,570±$30,876 · within the margin of this tract |
| Tract 3117.40 | 5th | $154,313±$21,243 · within the margin of this tract |
"Within the margin": the two incomes differ by less than their combined 90% margins, so the survey cannot say which is higher and the ranks between them are not firm.
Source: PlainCities ranks computed from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · How ranks are computed
How reliable are the figures for Census Tract 3122.09?
3 of the 17 figures for Census Tract 3122.09 on this page carry a coefficient of variation over 40% and are marked with a ring: they come from a small sample, so read them as rough.
A census tract's figures rest on a few hundred sampled households over five years, so its margins are wider than a city's. Two tracts differ only when the gap between them is larger than their combined 90% margin (the square root of the sum of the two squared margins). How to read a margin of error.
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026): margins of error as published · Check it at data.census.gov
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections