Alton, Illinois

Alton population, 2020 to 2024

Alton lost 669 residents from July 2020 to July 2024, a change of -2.6%. In the latest year it moved by -127. Among 330 Illinois places of 5,000 or more, that growth ranks 258th; the median place changed by -0.9%. The median place of 5,000+ in Illinois has 14,760 people, so Alton is 1.7 times that size.

Alton covers 15.67 square miles of land and 1.28 of water, for 1,593 people per square mile of land. The median Illinois place of 5,000+ has 2,177, so Alton is less dense than the typical town.

What county Alton is in

All of Alton's residents live in Madison County, which had 263,017 residents in 2024. Alton holds 9.5% of the county's population. The shaded shape is on the map above; dots mark the eight nearest places.

ZIP codes in Alton

2 ZIP Code Tabulation Areas (ZCTAs) overlap Alton by at least 10% of the ZCTA's or the city's land: 62002, 62018. ZCTAs are Census approximations of USPS ZIP code delivery areas. The list comes from the 2020 ZCTA to place relationship file, so a city that annexed land after 2020 may reach into ZIP codes not listed here.

Where Alton is

The Census internal point of Alton is at 38.903900, -90.151200. Springfield, the capital, is 66.3 miles NNE in a straight line. The nearest larger place is Edwardsville, IL (26,715 people), 11.7 miles away. The nearest city of 100,000 or more is St. Louis, MO, 19.2 miles away.

Daylight in Alton

At 38.90° N, Alton gets about 14 h 54 min of daylight around the June solstice and 9 h 26 min around the December solstice, a swing of 5 h 28 min. Figures are sunrise to sunset from the SunCalc model for June 21 and December 21, 2026.

Places near Alton

The eight nearest incorporated places of 1,000+ in Illinois, measured between internal points. The closest is East Alton, 2.7 miles away, with 5,621 people.