Map of Decatur, Illinois, United States

Decatur is a city in Illinois, United States, with a population of about 73,254. It lies at 39.8403°N, 88.9548°W, about 205 m above sea level. Decatur is about 1,029 km (639 mi) west of Washington, D.C., the capital. The nearest city on our map is Springfield, 59 km to the west.

Decatur at a glance

Where is Decatur?

• The 17th largest city in Illinois on this site.
• Located in the Northern and Western hemispheres.
• Daylight ranges from about 9 h 20 min on the shortest day to 15 h 00 min on the longest day (around 21 December and 21 June).

Cities near Decatur

• Springfield — 59 km west
• Champaign — 68 km northeast
• Urbana — 70 km northeast
• Bloomington — 72 km north
• Normal — 75 km north
• Pekin — 100 km northwest
• Peoria — 109 km northwest
• Terre Haute — 138 km east
• Florissant — 166 km southwest
• Belleville — 172 km southwest

Largest cities in Illinois

• Chicago — 2,664,452
• Aurora — 200,661
• Rockford — 148,278
• Joliet — 147,861
• Naperville — 147,100
• Peoria — 115,070
• Springfield — 114,394
• Elgin — 112,111
• Waukegan — 88,475
• Champaign — 86,096

Largest cities in United States

• New York City — 8,804,190
• Los Angeles — 3,820,914
• Brooklyn — 2,736,074
• Chicago — 2,664,452
• Queens — 2,316,841
• Houston — 2,314,157
• Phoenix — 1,650,070
• Philadelphia — 1,573,916
• San Antonio — 1,526,656
• Manhattan — 1,487,536

Map of United States and all its cities →

Other places named Decatur

• Decatur — Alabama, United States

Sources: place names, coordinates, populations and time zones from GeoNames (CC BY 4.0, data retrieved October 2026). Population figures are the latest values recorded in GeoNames; depending on the country they refer to the city proper, a municipality or a wider urban area, so they can differ from census or metro-area figures. Map © OpenStreetMap contributors.