What to know
Southwest also has a large Chicago operation at Midway (MDW), so confirm that your ticket says ORD.
Airport layout
O'Hare currently uses Terminals 1, 2, 3 and 5. Terminals 1 through 3 connect after security; Terminal 5 is reached by the Airport Transit System or eligible transfer bus.
Getting to the gate
International arrivals without U.S. preclearance generally process through Terminal 5 even when the airline departs from another terminal.
Connections
Allow extra time for a Terminal 5 connection because many transfers require another security screening.