City · Missouri
Arnold, Missouri
Arnold, city, in Jefferson County, Missouri. Arnold had 20,994 residents on July 1, 2025 by the Census Bureau's estimate, up 0.5% since 2020; the 2020 Census counted 20,858 and the ACS 2020-2024 5-year estimates put it at 20,956 (±52). GEOID 2901972.
Residents, July 2025 estimate
20,994
Census Bureau estimate (no margin published)
2020 Census count: 20,858 · ACS 2020-2024: 20,956 ±52
Median household income
$78,370
±$6,883 (90% margin)
Missouri: $70,702
Median home value
$220,000
±$8,959 (90% margin)
Missouri: $230,300
Median gross rent
$1,112
±$60 (90% margin)
Missouri: $1,033
Where is Arnold and what county is it in?
Arnold is a city in Jefferson County, Missouri. It covers 11.5 square miles of land, 1,809 residents per square mile in 2020.
Arnold 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 Arnold, and is it growing?
The Census Bureau estimates that 20,994 people lived in Arnold on July 1, 2025, up 0.5% since 2020, slower than Missouri (+1.9%). The 2020 Census counted 20,858 residents. The 2020-2024 American Community Survey, a five-year sample, puts the population at 20,956 (±52).
| Measure | Arnold | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 20,956 ±52 | 229,458 | −190 |
| Households | 8,394 ±341 | 88,309 | no clear change |
| Average household size | 2.49 ±0.10 | 2.58 | no clear change |
| Housing units | 8,982 ±329 | 93,955 | no clear change |
Arnold's population since 2000
From 19,965 in 2000 to 20,994 in 2025: up 5.2%. The 2000, 2010 and 2020 figures are census counts, each for Arnold 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 Arnold?
The median resident of Arnold is 39.7 years old; 20.7% are under 18 and 19.5% are 65 or older. The largest group is non-Hispanic white residents at 88.0%, then non-Hispanic residents of two or more races at 6.7%. 5.3% of residents were born outside the United States.
| Measure | Arnold | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 39.7 ±2.5 | 40.3 | no clear change |
| Under 18 years | 20.7% ±2.1 pts | 22.5% | – |
| 65 years and over | 19.5% ±2.0 pts | 16.7% | – |
| Male | 48.5% ±2.3 pts | 50.0% | – |
| Hispanic or Latino (any race) | 2.6% ±1.2 pts | 2.6% | no clear change |
| White alone, not Hispanic | 88.0% ±3.6 pts | 88.5% | −8.3 pts |
| Black or African American alone, not Hispanic | 0.2% ±0.2 pts | 1.0% | – |
| Asian alone, not Hispanic | 1.8% ±1.1 pts | 1.0% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±0.1 pts | 0.1% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.1% ±0.1 pts | 0.0% | – |
| Two or more races, not Hispanic | 6.7% ±3.0 pts | 6.5% | – |
| Some other race alone, not Hispanic | 0.4% ±0.4 pts | 0.3% | – |
| Born outside the United States | 5.3% ±1.5 pts | 2.3% | no clear change |
| Speak a language other than English at home (age 5+) | 7.8% ±2.1 pts | 3.3% | – |
| Civilian veterans (age 18+) | 6.3% ±1.6 pts | 7.3% | – |
| With a disability | 14.2% ±2.3 pts | 13.3% | – |
| No health insurance coverage | 7.5% ±2.6 pts | 6.6% | no clear change |
| High school graduate or higher (age 25+) | 90.7% ±2.0 pts | 92.0% | – |
| Bachelor's degree or higher (age 25+) | 25.4% ±3.5 pts | 24.7% | +5.8 pts |
| Graduate or professional degree (age 25+) | 8.1% ±2.4 pts | 8.0% | – |
| Lived in the same house a year earlier | 92.2% ±2.1 pts | 90.1% | – |
| Moved from another state in the past year | 0.6% ±0.4 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 Arnold earn?
Half of Arnold's 8,394 households earn less than $78,370 a year (±$6,883), against $82,851 in Jefferson County and $70,702 in Missouri. In 2015-2019 it was $82,050 in 2024 dollars; the margins of error cannot tell the two periods apart. 8.2% of residents live below the poverty line.
| Measure | Arnold | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $78,370 ±$6,883 | $82,851 | no clear change |
| Mean household income | $91,307 ±$6,926 | $98,813 | – |
| Per capita income | $37,598 ±$2,682 | $39,160 | no clear change |
| People below the poverty line | 8.2% ±3.2 pts | 9.0% | no clear change |
| Children under 18 below the poverty line | 12.7% ±8.0 pts | 11.6% | no clear change |
| Households receiving SNAP | 3.6% ±1.3 pts | 7.1% | – |
| Households with a computer | 96.2% ±1.5 pts | 95.7% | – |
| Households with a broadband subscription | 91.4% ±3.6 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 Arnold?
Owners occupy 79.8% of Arnold's occupied homes and renters 20.2%. The median owner-occupied home is valued at $220,000 by its owner (±$8,959). The median renter pays $1,112 a month including utilities, and 28.6% of renters pay 35% or more of their income on rent.
| Measure | Arnold | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $220,000 ±$8,959 | $237,200 | +$26,043 |
| Median gross rent | $1,112 ±$60 | $979 | no clear change |
| Renters paying 35% or more of income on rent | 28.6% ±10.5 pts | 29.7% | no clear change |
| Median monthly owner costs, with a mortgage | $1,495 ±$145 | $1,545 | – |
| Owner-occupied homes | 79.8% ±3.9 pts | 82.2% | +6.5 pts |
| Renter-occupied homes | 20.2% ±3.9 pts | 17.8% | – |
| Housing units | 8,982 ±329 | 93,955 | no clear change |
| Homeowner vacancy rate | 1.5% ±1.6 pts | 1.0% | – |
| Rental vacancy rate | 3.4% ±3.9 pts | 1.8% | – |
| Single-family detached homes | 79.0% ±3.3 pts | 79.9% | – |
| Mobile homes | 3.5% ±1.1 pts | 9.0% | – |
| Built 2020 or later | 0.9% ±0.5 pts | 2.2% | – |
| Built 2010 to 2019 | 5.3% ±1.6 pts | 9.2% | – |
| Built 1939 or earlier | 1.8% ±1.0 pts | 3.5% | – |
| Households with no vehicle | 2.7% ±1.4 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 Arnold building?
Builders took permits for 16 new housing units in Arnold in 2025 (16 in single-family houses), 0.8 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 Arnold work and get to work?
84.8% of Arnold's workers drive alone and 8.1% work from home. The average trip to work takes 27.2 minutes. The unemployment rate in 2020-2024 averaged 2.8%.
| Measure | Arnold | Jefferson County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 65.1% ±3.1 pts | 66.0% | – |
| Unemployment rate | 2.8% ±1.0 pts | 3.2% | no clear change |
| Drove alone to work | 84.8% ±2.4 pts | 79.5% | – |
| Carpooled | 6.2% ±1.7 pts | 7.2% | – |
| Public transportation | 0.0% ±0.3 pts | 0.1% | – |
| Walked | 0.6% ±0.5 pts | 0.6% | – |
| Worked from home | 8.1% ±2.0 pts | 11.5% | +6.0 pts |
| Mean travel time to work | 27.2 min ±1.4 | 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 Arnold?
4 census tracts lie mostly in Arnold, and 5 more reach into it (2020 census blocks). Their median household incomes run from $71,587 (Tract 7001.18) to $84,250 (Tract 7001.21).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 7001.18Jefferson County | 5,851 | $71,587 |
| Tract 7001.21Jefferson County | 4,019 | $84,250 |
| Tract 7001.11Jefferson County | 3,986 | $73,604 |
| Tract 7001.22Jefferson County | 4,159 | $82,938 |
| Tract 7001.15Jefferson County | 4,102 | $77,672 |
| Tract 7001.17Jefferson County | 6,561 | $85,644 |
| Tract 7001.13Jefferson County | 4,303 | $112,969 |
| Tract 7001.14Jefferson County | 5,508 | $77,382 |
| Tract 7001.19Jefferson County | 1,906 | $80,438 |
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 Arnold) · Census block assignment files
How does Arnold compare with other places in Missouri?
By the Census Bureau's July 2025 estimates, Arnold is the 1,859th-most populous of the 19,476 U.S. incorporated places that have one and the 35th-most populous of 936 in Missouri.
Arnold ranks 91st 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 | 35th | 936 |
| Growth 2020-2025 (PEP) | 218th | 394 |
| Residents per square mile | 84th | 420 |
| Median household income | 91st | 416 |
| Per capita income | 95th | 420 |
| Median home value | 101st | 416 |
| Median gross rent | 92nd | 398 |
| Poverty rate | 299th | 373 |
| Bachelor's degree or higher | 143rd | 404 |
| Median age | 163rd | 420 |
| Owner-occupied share | 80th | 418 |
| Work from home | 184th | 270 |
| Travel time to work | 94th | 420 |
Arnold's figures with every place in Missouri (CSV)
Every place in Missouri, sortable · Compare Arnold 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 Arnold?
9 of the 57 figures for Arnold 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 Arnold 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 Arnold.