United Airlines is one of the most popular airlines in the world and it has a major hub at Chicago O'Hare International Airport. The United Airlines Chicago address is 1020 W. O'Hare Ave, Chicago, IL 60666. This address is used for all flights departing from and arriving at Chicago O'Hare International Airport. With this address, passengers can easily find their way to the airport and make sure they are on time for their flight.