From UA's website welcoming CO to *A:

Travel easily across two of the greatest networks in the air.
We are working closely with Continental to ensure improved connections and easier travel between our two networks, which provide complimentary strengths in different regions of the world. To make your experience as simple as possible, Continental and United are now located in the same terminal at Chicago O'Hare, Cincinnati, Honolulu, Los Angeles, Salt Lake City, Beijing and Shanghai. Future co-locations include Cleveland, Denver, Dallas/Ft. Worth, San Jose, CA, Paris Charles de Gaulle and Tokyo Narita.