UA 654 then UA 4772 at O'Hare
Washington National → Chicago → Columbia Regional
Timetable, Chicago time
18:29UA 654 from Washington National at the gate
12:45UA 4772 to Columbia Regional leaves the gate
18 h 16 apart on the timetable, overnight
UA 4772 leaves 18 h 16 after UA 654 arrives on the timetable: more than half a day, so not a connection we count.