Geography of Illinois
Geography of Illinois: location, coordinates, elevation, terrain and the places around it.
Geography of Illinois
Gateway Arch National Park is 85 mi to the south, St. Louis is 85 mi to the south, Missouri is 159 mi to the south-west and Indiana is 185 mi to the east.
Map of Illinois
Interactive map with nearby places. Switch between street, terrain and satellite views.
Coordinates: 39°46′54.1″N 89°39′0.4″W (39.7817, -89.6501)
Quick facts about Illinois
| Type | State |
|---|---|
| Country | United States |
| Continent | North America |
| Coordinates | 39°46′54.1″N 89°39′0.4″W (39.7817, -89.6501) |
| Capital | Springfield |
| Population | 12.600.000 |
| Area | 57.913 sq mi |
| Abbreviation | IL |
| Time zone | America/Chicago |
| Local time | 3:52 PM (UTC-05:00) |
| Best months | August, September and October |
| Climate | Continental |
Geography by city in Illinois
1 cities mapped in this atlas
Geography by state park in Illinois
1 state and provincial parks mapped in this atlas
Geography by county in Illinois
1 counties mapped in this atlas
Geography by lake in Illinois
1 lakes mapped in this atlas
Summary
Illinois is a state in United States. Illinois is a US state with its capital at Springfield. It has a population of about 12.6 million. The capital is Springfield.
Right now it is 57°F (14°C) in Illinois with mainly clear. It feels like 55°F. Today runs from 45°F to 78°F. Chance of precipitation is 0%. Sightseeing conditions score 9.6/10 - excellent - go now.
The best time to visit Illinois is August, September and October. The climate is continental. January, February and December tend to be the least comfortable months. July is the warmest month with average highs near 85°F, while January is the coldest with lows near 19°F.
The closest major airport is O'Hare International Airport (ORD), about 177 mi away. Nearby highlights include Starved Rock State Park, Lake Michigan, Gateway Arch National Park and Indiana Dunes National Park.
In plain terms. Today is warmer than average for October. The forecast high of 78°F is 9.2°F above the 69°F typical for this month. The best window to be outside is roughly 11 AM to 2 PM, when temperature, rain chance and wind line up best. hiking is the strongest bet in Illinois today at 9.8/10. No weather-related travel disruption is expected today. Roads and airports should run normally.
Compiled from this page's own data: atlas facts plus live Open-Meteo readings.
Climate in Illinois month by month
Average high, average low and total rainfall, based on three years of reanalysis data.
| Month | Avg high | Avg low | Rainfall | Rating |
|---|---|---|---|---|
| January | 33° | 19° | 2,4 in | ★★☆☆☆ |
| February | 46° | 27° | 0,8 in | ★★★☆☆ |
| March | 60° | 39° | 3,5 in | ★★★☆☆ |
| April | 67° | 48° | 5,3 in | ★★★☆☆ |
| May | 74° | 56° | 3,9 in | ★★★★☆ |
| June | 83° | 66° | 4,6 in | ★★★★☆ |
| July | 85° | 69° | 5,1 in | ★★★★☆ |
| August | 83° | 67° | 3,0 in | ★★★★☆ |
| September | 82° | 63° | 1,3 in | ★★★★★ |
| October | 69° | 50° | 1,5 in | ★★★★☆ |
| November | 54° | 38° | 3,1 in | ★★★☆☆ |
| December | 43° | 29° | 2,4 in | ★★☆☆☆ |
Climate type: Continental. Source: Open-Meteo archive (ERA5).
Explore Illinois
Every topic we hold for this place, and the same topic for the places around it.
Geography for related places
Frequently asked questions
Where is Illinois?
Illinois is a state in United States. Its coordinates are 39.7817, -89.6501. It lies in North America.
What is the weather like in Illinois right now?
It is currently 57°F (14°C) with mainly clear. Humidity is 71% and wind is 4 mph.
When is the best time to visit Illinois?
August, September and October offer the most comfortable conditions in Illinois, which has a continental climate. January, February and December are usually the hardest months for outdoor plans.
What time zone is Illinois in?
Illinois observes America/Chicago (UTC-05:00). The local time is 3:52 PM.
How many people live in Illinois?
Illinois has a population of approximately 12.6 million.
What is the nearest airport to Illinois?
The closest airports are O'Hare International Airport (ORD), 177 mi away and Nashville International Airport (BNA), 300 mi away.
What are the top things to do in Illinois?
Popular options include Starved Rock State Park, Lake Michigan, Gateway Arch National Park and Indiana Dunes National Park.
What places are in Illinois?
Illinois covers 4 places in this atlas, including Chicago, Starved Rock State Park, Cook County and Lake Michigan.
Related articles
Data sources and methodology
| Place data | USPOTUS Atlas dataset (us-states) - coordinates, hierarchy and facts. |
|---|---|
| Map tiles | OpenStreetMap contributors, CARTO and Esri. |
| Elevation | Open-Meteo digital elevation model where the dataset has no value. |
| Method | Scores, comparisons and advice on this page are computed from the inputs above. Distances are straight-line. Nothing is estimated where data is missing - the block is simply not shown. |
Last updated October 26, 2026 at 3:52 PM local time. Live blocks refresh every 15 minutes; climate averages monthly.
