Originally Posted by
MADPhil
When you arrive on any international flight at O'Hare you must clear immigration and customs. You will then be land side and unable to access any lounges in T5.
in most practice, this is good advice, but I don't believe the TSA in terminal 5 do more than scan a valid same day boarding pass and check ID. It's doubtful they would prevent you access to the dptr level, regardless of which terminal your flight was leaving from