Climate/Weather: National Weather Service, Illinois State Climatologist Office, UofI/NCSA Weather Info

Counties (102): County Sites, State and County Quick Facts

Geology: Illinois State Geological Survey, Illinois State Museum Geology Online, United States Geological Survey; 56,400 sq. mi.; 24th largest state

Geographic Center of Illinois: Chestnut

Geography: Illinois Geographic Information Council

Highest Point: Charles Mound; 1235 feet, 45th highest state

Inland Water: 700 sq.mi., state with 29th largest amount of inland water

Largest Cities: Chicago, Rockford, Peoria, Springfield, Aurora

Largest Lakes: Carlyle Lake, 24,580 acres - Rend Lake, 18,900 acres

Land Area: 56,400 sq. mi., 385 miles long and 218 miles wide, 24th largest state

Latitude:36.9540° to 42.4951°N

Longitude:87.3840° to 91.4244° W

Lowest Point: Mississippi River; 279 feet, 33rd lowest state low point

Maps: Geology and Mining, Hydrology and Water Resources, Natural History, Public Land Survey System and Base Maps, Datasets by County

Border States - Indiana, Iowa, Michigan, Kentucky, Missouri, Wisconsin

Topography: Image

Parks and Forest