DL 2804 then UA 3921 at O'Hare
Boston → Chicago → Washington National
Timetable, Chicago time
22:40DL 2804 from Boston at the gate
22:00UA 3921 to Washington National leaves the gate
23 h 20 apart on the timetable, overnight
UA 3921 leaves 23 h 20 after DL 2804 arrives on the timetable: more than half a day, so not a connection we count.