Chicago, officially the City of Chicago, is the most populous city in the U.S. state of Illinois, and the third-most-populous city in the United States. With an estimated population of over 2,693,976 people, it is also the most populous city in the Midwestern United States. Chicago is the county seat of Cook County, the second-most-populous county in the US, with a small portion of the north-west side of the city extending into DuPage County near O'Hare Airport. Chicago is the principal city of the Chicago metropolitan area, often referred to as Chicagoland. At nearly 10 million people, the metropolitan area is the third most populous in the United States.
Estimates show that Chicago has more than 213,358 businesses, including over 8,497 professional service firms and more than 6,161 Attorneys.
Chicago is the #20 city in the world according to the Global Financial Centres Index (GPCI) which evaluates and ranks the competitiveness of the major financial centres of the world according to a wide range of criteria – Human Capital, Business, Finance, Infrastructure and Reputation.
Chicago is the #26 city in the world according to the Global Power City Index (GPCI) which evaluates and ranks the major cities of the world according to their “magnetism”, or their comprehensive power to attract people, capital, and enterprises from around the world. It does so through measuring 6 functions—Economy, Research and Development, Cultural Interaction, Liveability, Environment, and Accessibility.
Chicago is an Alpha city according to the Globalization and World Cities Research Network (GaWC) which evaluates and ranks the relationships between world cities in the context of globalisation.
Alpha level cities are linked to major economic states and regions and into the world economy.