The largest municipality by population is Chicago with 2,746, 388 residents, while the smallest by population is Valley City with 14 residents.
Get a spreadsheet with the most recent demographics for population, income, housing, and more for all cities in Illinois.The peak population of Chicago Heights was 33,070 in 1990, and its current population of 26,905 represents a decline of 18.6% from its peak. Among the 100 largest cities in Illinois, the fastest-shrinking city is Chicago Heights, whose population has declined 17.8% since 2000. The second largest city is Aurora, with a population of 179,266, and it is the 144th largest city in the United States.
The evolution of the population of the state of Illinois according to the results of the census and the latest official estimates. The major cities in Illinois are Chicago, Aurora, Joliet, Naperville, Rockford, Elgin, Springfield, and Peoria.