city of chicago estimated population
For other uses, see Chicago (disambiguation). Chicago (/Êáµ»ËkÉËÉ¡oÊ/ or /Êáµ»ËkÉËÉ¡oÊ/), officially the City of Chicago, is the third-most populous city in the United States. With over 2.7 million residents, it is the most populous city in the state of Illinois, and the Midwestern United States. It is the county seat of Cook County.