Illinois: elevation, cities and highest point
Illinois has 12,719,141 people (2025) and 102 counties. Its highest point is Charles Mound, at 1,235 ft, and its lowest, the Mississippi River, at 279 ft. Here you’ll find the elevation of its capital, its cities over 100,000 people and its summit, with a map of its counties.
By the All Map Tools Team
- Population (2025)
- 12,719,141
- The 6th most populous of the 50 states
- Land area
- 55,513 sq mi
- The 24th largest state
- Counties
- 102
- According to the Census (2025)
- Lowest point
- 279 ft
- Mississippi River
Map of Illinois’s counties
- Capital’s county
- County with a city page
- City, by elevation
- Highest point
Elevation
The capital, Springfield, sits at 600 ft (183 m): the 22nd highest of the 50 state capitals. Illinois’s highest point, Charles Mound, is 189 mi away in a straight line and 635 ft higher.
Between its highest point (1,235 ft) and its lowest (279 ft) there’s 956 ft of relief, according to the USGS table. Of the 50 state high points, Illinois’s is the 45th highest.
Illinois has 8 cities with a page. The highest is Elgin, at 740 ft, and the lowest is Peoria, at 502 ft: 238 ft apart.
Illinois borders 5 states. Their highest points are Timms Hill, in Wisconsin (1,951 ft), Hoosier Hill, in Indiana (1,257 ft), Hawkeye Point, in Iowa (1,670 ft), Taum Sauk Mountain, in Missouri (1,772 ft), and Black Mountain, in Kentucky (4,145 ft): Illinois’s is the 6th highest of the 6. Their capitals: Madison (875 ft), Indianapolis (730 ft), Des Moines (872 ft), Jefferson City (630 ft), and Frankfort (504 ft).
- Charles Mound 1,235 ft
- Springfield 600 ft
- Chicago 588 ft
Cities of 100,000 to 250,000 people (6)
Population
Illinois had 12,719,141 residents on July 1, 2025, according to Census Bureau estimates, 0.8% fewer than in April 2020 (12,821,741). Across 55,513 sq mi of land, that’s 229 people/sq mi.
Its most populous place is Chicago, with 2,731,585 people. The Census counts 1,461 cities, towns and census-designated places (CDPs) in Illinois.
| Place | Population | Land area | Elevation |
|---|---|---|---|
| Chicago | 2,731,585 | 228 sq mi | 588 ft |
| Aurora | 181,505 | 45.2 sq mi | 675 ft |
| Naperville | 153,114 | 39.4 sq mi | 709 ft |
| Joliet | 152,241 | 66.3 sq mi | 541 ft |
| Rockford | 147,384 | 65.4 sq mi | 717 ft |
| Elgin | 115,476 | 38.2 sq mi | 740 ft |
| Springfield | 112,989 | 61.3 sq mi | 600 ft |
| Peoria | 110,920 | 48.2 sq mi | 502 ft |
| Champaign | 91,195 | 23.0 sq mi | — |
| Waukegan | 87,940 | 24.3 sq mi | — |
Neighboring states
Tools
Frequently asked questions
What is the highest point in Illinois?
Charles Mound, at 1,235 ft, according to the USGS table. It’s the 45th highest of the 50 state high points.
What is the lowest point in Illinois?
The Mississippi River, at 279 ft, according to the same USGS table.
What is the elevation of Springfield, the capital?
600 ft above sea level, at its reference point in the USGS gazetteer. It’s the 22nd highest state capital.
What is the highest city in Illinois?
Of the cities with a page (the capital and those over 100,000 people), Elgin, at 740 ft. Some smaller towns are higher: look them up with the point elevation tool.
How many counties does Illinois have?
102, according to the Census Bureau in 2025.
Sources
- Population, land area and counties: U.S. Census Bureau (Vintage 2025 estimates and 2025 Gazetteer), public domain.
- Highest and lowest points: USGS, “Elevations and Distances in the United States” (and, for Denali, the 2015 survey), public domain.
- City elevations: USGS 3DEP at each city’s GNIS point, public domain.
- County map: U.S. Census Bureau, 2025 Cartographic Boundary Files (1:500,000).
Methodology and sources · Spotted a mistake? Let us know