Terminal 1 is in the main airport core alongside Terminal 2 and Terminal 3. By road it is the first terminal reached from Interstate I-190 and has clear signs. It is the United / United Express terminal and also handles Lufthansa's departing flights. (All international flights into O'Hare arrive at Terminal 5.)
The terminal is on two levels, the upper level for departures and arrivals, the lower for baggage claim and ground transportation. Beyond the ticketing area the terminal has two large concourses - B and C. Concourse B is adjacent to the main terminal area, Concourse C is reached by underground moving walkways.