City · Missouri
Byrnes Mill, Missouri
Byrnes Mill, city, in Jefferson County, Missouri. Byrnes Mill had 3,183 residents on July 1, 2025 by the Census Bureau's estimate, up 0.3% since 2020; the 2020 Census counted 3,173 and the ACS 2020-2024 5-year estimates put it at 3,189 (±20). GEOID 2910240.
Residents, July 2025 estimate
3,183
Census Bureau estimate (no margin published)
2020 Census count: 3,173 · ACS 2020-2024: 3,189 ±20
Median household income
$98,576
±$29,990 (90% margin)
Missouri: $70,702
Median home value
$306,200
±$92,484 (90% margin)
Missouri: $230,300
Median gross rent
$1,137
±$33 (90% margin)
Missouri: $1,033
Where is Byrnes Mill and what county is it in?
Byrnes Mill is a city in Jefferson County, Missouri. It covers 5.1 square miles of land, 617 residents per square mile in 2020.
Byrnes Mill is in the St. Louis, MO-IL metropolitan statistical area, which takes in 15 counties (Census Bureau delineation, July 2023).
Source: 2024 Gazetteer and 2020 place-by-county files, U.S. Census Bureau · Census reference files
How many people live in Byrnes Mill, and is it growing?
The Census Bureau estimates that 3,183 people lived in Byrnes Mill on July 1, 2025, up 0.3% since 2020, slower than Missouri (+1.9%). The 2020 Census counted 3,173 residents. The 2020-2024 American Community Survey, a five-year sample, puts the population at 3,189 (±20).
| Measure | Byrnes Mill | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 3,189 ±20 | 229,458 | +219 |
| Households | 1,200 ±131 | 88,309 | no clear change |
| Average household size | 2.66 ±0.29 | 2.58 | no clear change |
| Housing units | 1,232 ±146 | 93,955 | no clear change |
Byrnes Mill's population since 2000
From 2,376 in 2000 to 3,183 in 2025: up 34.0%. The 2000, 2010 and 2020 figures are census counts, each for Byrnes Mill as it was drawn that year: a place that annexed land, or a community that has since incorporated, covered a different area then. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.
Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); Census PEP Vintage 2025 (SUB-EST2025, CO-EST2025); 2020 Census P.L. 94-171 · Check it at data.census.gov
Who lives in Byrnes Mill?
The median resident of Byrnes Mill is 37.9 years old; 25.1% are under 18 and 15.6% are 65 or older. The largest group is non-Hispanic white residents at 85.4%, then non-Hispanic residents of two or more races at 12.2%.
| Measure | Byrnes Mill | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 37.9 ±4.6 | 40.3 | no clear change |
| Under 18 years | 25.1% ±6.3 pts | 22.5% | – |
| 65 years and over | 15.6% ±6.3 pts | 16.7% | – |
| Male | 53.1% ±6.6 pts | 50.0% | – |
| Hispanic or Latino (any race) | 0.4% ±0.7 pts | 2.6% | – |
| White alone, not Hispanic | 85.4% ±12.5 pts | 88.5% | no clear change |
| Black or African American alone, not Hispanic | 1.9% ±2.8 pts | 1.0% | – |
| Asian alone, not Hispanic | 0.0% ±1.1 pts | 1.0% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±1.1 pts | 0.1% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±1.1 pts | 0.0% | – |
| Two or more races, not Hispanic | 12.2% ±12.3 pts | 6.5% | – |
| Some other race alone, not Hispanic | 0.0% ±1.1 pts | 0.3% | – |
| Born outside the United States | 0.0% ±1.1 pts | 2.3% | – |
| Speak a language other than English at home (age 5+) | 1.6% ±1.7 pts | 3.3% | – |
| Civilian veterans (age 18+) | 7.3% ±3.9 pts | 7.3% | – |
| With a disability | 20.2% ±7.5 pts | 13.3% | – |
| No health insurance coverage | 11.9% ±7.2 pts | 6.6% | no clear change |
| High school graduate or higher (age 25+) | 93.4% ±4.9 pts | 92.0% | – |
| Bachelor's degree or higher (age 25+) | 24.4% ±9.1 pts | 24.7% | no clear change |
| Graduate or professional degree (age 25+) | 10.9% ±5.2 pts | 8.0% | – |
| Lived in the same house a year earlier | 93.3% ±5.3 pts | 90.1% | – |
| Moved from another state in the past year | 1.5% ±2.5 pts | 1.2% | – |
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 Byrnes Mill earn?
Half of Byrnes Mill's 1,200 households earn less than $98,576 a year (±$29,990), against $82,851 in Jefferson County and $70,702 in Missouri. In 2015-2019 it was $85,635 in 2024 dollars; the margins of error cannot tell the two periods apart. 21.1% of residents live below the poverty line.
| Measure | Byrnes Mill | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $98,576 ±$29,990 | $82,851 | no clear change |
| Mean household income | $107,382 ±$17,799 | $98,813 | – |
| Per capita income | $41,320 ±$7,289 | $39,160 | no clear change |
| People below the poverty line | 21.1% ±10.1 pts | 9.0% | +13.2 pts |
| Children under 18 below the poverty line | 27.9% ±26.5 pts | 11.6% | – |
| Households receiving SNAP | 2.5% ±3.2 pts | 7.1% | – |
| Households with a computer | 96.0% ±4.0 pts | 95.7% | – |
| Households with a broadband subscription | 86.7% ±8.7 pts | 91.7% | – |
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 Byrnes Mill?
Owners occupy 81.3% of Byrnes Mill's occupied homes and renters 18.7%. The median owner-occupied home is valued at $306,200 by its owner (±$92,484). The median renter pays $1,137 a month including utilities.
| Measure | Byrnes Mill | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $306,200 ±$92,484 | $237,200 | no clear change |
| Median gross rent | $1,137 ±$33 | $979 | no clear change |
| Renters paying 35% or more of income on rent | 28.6% ±38.7 pts | 29.7% | – |
| Median monthly owner costs, with a mortgage | $1,671 ±$275 | $1,545 | – |
| Owner-occupied homes | 81.3% ±12.4 pts | 82.2% | no clear change |
| Renter-occupied homes | 18.7% ±12.4 pts | 17.8% | – |
| Housing units | 1,232 ±146 | 93,955 | no clear change |
| Homeowner vacancy rate | 0.0% ±3.5 pts | 1.0% | – |
| Rental vacancy rate | 0.0% ±14.4 pts | 1.8% | – |
| Single-family detached homes | 63.5% ±11.6 pts | 79.9% | – |
| Mobile homes | 34.1% ±11.6 pts | 9.0% | – |
| Built 2020 or later | 2.4% ±3.4 pts | 2.2% | – |
| Built 2010 to 2019 | 18.3% ±8.1 pts | 9.2% | – |
| Built 1939 or earlier | 4.3% ±4.8 pts | 3.5% | – |
| Households with no vehicle | 2.9% ±3.8 pts | 3.7% | – |
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 many new homes is Byrnes Mill building?
Builders took permits for 3 new housing units in Byrnes Mill in 2025 (3 in single-family houses), 0.9 per 1,000 residents against 2.8 across Missouri.
Counts of units in permits a local office issued; not every permitted unit is built. A year marked with months was reported for part of the year.
Source: Building Permits Survey, annual place files 2019-2025, U.S. Census Bureau · Census Building Permits Survey
How do people in Byrnes Mill work and get to work?
70.8% of Byrnes Mill's workers drive alone and 20.3% work from home. The average trip to work takes 38.1 minutes.
| Measure | Byrnes Mill | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 60.6% ±7.5 pts | 66.0% | – |
| Unemployment rate | 9.8% ±8.4 pts | 3.2% | – |
| Drove alone to work | 70.8% ±12.5 pts | 79.5% | – |
| Carpooled | 6.8% ±5.9 pts | 7.2% | – |
| Public transportation | 0.0% ±2.6 pts | 0.1% | – |
| Walked | 0.0% ±2.6 pts | 0.6% | – |
| Worked from home | 20.3% ±10.1 pts | 11.5% | – |
| Mean travel time to work | 38.1 min ±12.5 | 30.6 min | no clear change |
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 census tracts are in Byrnes Mill?
1 census tract lies mostly in Byrnes Mill, and 3 more reach into it (2020 census blocks).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 7003.02Jefferson County | 5,798 | $99,317 |
| Tract 7002.07Jefferson County | 3,163 | $83,718 |
| Tract 7004.02Jefferson County | 7,198 | $133,854 |
| Tract 7005.04Jefferson County | 3,924 | $97,083 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 block assignment files (tract share = share of the tract's census blocks in Byrnes Mill) · Census block assignment files
How does Byrnes Mill compare with other places in Missouri?
By the Census Bureau's July 2025 estimates, Byrnes Mill is the 6,148th-most populous of the 19,476 U.S. incorporated places that have one and the 182nd-most populous of 936 in Missouri.
Byrnes Mill ranks 50th of 416 places in Missouri with 1,000 or more residents and a reliable estimate, by median household income.
| Measure | Rank | Of |
|---|---|---|
| Population, July 2025 estimate | 182nd | 936 |
| Growth 2020-2025 (PEP) | 220th | 394 |
| Residents per square mile | 326th | 420 |
| Median household income | 50th | 416 |
| Per capita income | 75th | 420 |
| Median home value | 49th | 416 |
| Median gross rent | 82nd | 398 |
| Poverty rate | 93rd | 373 |
| Bachelor's degree or higher | 153rd | 404 |
| Median age | 236th | 420 |
| Owner-occupied share | 68th | 418 |
| Work from home | 39th | 270 |
| Travel time to work | 6th | 420 |
Byrnes Mill's figures with every place in Missouri (CSV)
Every place in Missouri, sortable · Compare Byrnes Mill with other places
Source: PlainCities ranks computed from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How reliable are the figures for Byrnes Mill?
23 of the 57 figures for Byrnes Mill 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.
The American Community Survey samples about one household in eight over five years, so every figure is an estimate with a 90% margin of error (shown under each value). A ring marks an estimate whose coefficient of variation is over 40%. A change is called only when the gap between the two periods is larger than their combined 90% margin (the square root of the sum of the two squared margins), the Census Bureau's test. 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 · ACS technical documentation
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for Byrnes Mill are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' public schools in Byrnes Mill.