Alton, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates
The population of Alton, Illinois is 25,430 as of the 2023 American Community Survey, making it the 87th-largest city in Illinois. The median household income is $53,005, the median home value is $99,500, and the median age is 38.4.
The population has declined 10.5% since 2010 (27,898 → 24,967).
25,430
Population
1623
People / sq mi
$53,005
Median Income
$99,500
Median Home Value
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Alton covers 15.7 sq mi of land at 1623 people per square mile.
About Alton, IL
In Alton, home values do the distinguishing — a median of $99,500. With 25,430 residents, Alton is a city in Illinois.
Earnings trail the nation, with the median household making $53,005, below the US median of $78,538. Poverty is among the highest of comparable US cities: 17.7%, above the national 12.4%. Real estate is inexpensive, with a typical home worth only $99,500, with typical rent around $948.
Fewer adults hold degrees here than in most comparable places — 21.2%, below the national 35.0%. Around 8.4% of workers work from home, below the national 14.0%, and the average commute runs about 24 minutes each way.
Alton city Population History (2010-2024)
The city of Alton city had a population of 27,898 in 2010 and 24,967 in 2024, a -10.5% growth over 14 years. The peak was 27,898 in 2010. Average annual growth rate: -0.79%.
24,967
Population (2024)
27,898
Population (2010)
27,898
Peak (2010)
-0.79%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 27,898 |
| 2011 | 27,702 |
| 2012 | 27,505 |
| 2013 | 27,380 |
| 2014 | 27,194 |
| 2015 | 27,001 |
| 2016 | 26,865 |
| 2017 | 26,707 |
| 2018 | 26,467 |
| 2019 | 26,208 |
| 2020 | 25,636 |
| 2021 | 25,454 |
| 2022 | 25,250 |
| 2023 | 25,094 |
| 2024 | 24,967 |
Race & Ethnicity
| White | 66.7% |
| Black or African American | 24.2% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 1.0% |
| Two or More Races | 0.0% |
Economy & Income
$53,005
Median Household Income
$28,970
Per Capita Income
17.7%
Poverty Rate
3.1%
Unemployment Rate
Housing
$99,500
Median Home Value
$948
Median Rent
57.1%
Owner-Occupied
Education
90.8%
High School+
21.2%
Bachelor's+
Commute
1.6%
Drive Alone
76.1%
Public Transit
8.4%
Work From Home
23.7 min
Avg Commute
Community Profile
27.2%
Foreign Born
96.3%
Non-English at Home
8.7%
Veterans
21.7%
With Disability
93.6%
Health Insurance
92.7%
Internet Access
Employment by Industry
| Professional, Scientific & Management | 25.2% |
| Education, Health Care & Social Services | 11.7% |
| Finance, Insurance & Real Estate | 10.0% |
| Manufacturing | 9.3% |
| Retail Trade | 6.8% |
| Arts, Entertainment & Food Services | 5.7% |
| Construction | 5.6% |
| Public Administration | 4.1% |
| Information | 3.9% |
| Transportation & Warehousing | 1.3% |
| Agriculture & Mining | 0.8% |
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Frequently Asked Questions
Alton, Illinois has a population of 25,430 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 87th-largest city in Illinois.
The median household income in Alton, Illinois is $53,005, with 17.7% of residents living below the federal poverty level.
The median home value in Alton, Illinois is $99,500, with median monthly rent at $948 and a homeownership rate of 57.1%.
The median age in Alton, Illinois is 38.4 years. The population is 48.0% male and 52.0% female.
The population has declined 10.5% since 2010 (27,898 → 24,967).
Alton city, IL Climate
Alton city, IL has an average annual temperature of 12.6°C (55°F) and receives about 968 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
12.6°C
Avg Temp
968
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -2° / 28° | 48 mm |
| February | 1° / 33° | 53 mm |
| March | 7° / 44° | 87 mm |
| April | 13° / 55° | 94 mm |
| May | 18° / 65° | 103 mm |
| June | 23° / 74° | 93 mm |
| July | 26° / 78° | 95 mm |
| August | 25° / 76° | 84 mm |
| September | 20° / 69° | 82 mm |
| October | 14° / 57° | 70 mm |
| November | 7° / 45° | 83 mm |
| December | 1° / 33° | 76 mm |
1970–2000 normals from WorldClim 2.1 (~9 km grid). Precipitation can be less precise near mountains or coastlines, where rainfall varies sharply over short distances.
Best time to visit Alton city, IL
The most comfortable months to visit Alton city, IL are typically September, June and August, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 31°C high). The coldest is January (near -7°C low). May is usually the wettest month.
Where to stay near Alton
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.