UA 1580 then DL 5679 at Boston
Chicago O'Hare → Boston → Louisville
Timetable, Boston time
16:11UA 1580 from Chicago O'Hare at the gate
10:25DL 5679 to Louisville leaves the gate
18 h 14 apart on the timetable, overnight
DL 5679 leaves 18 h 14 after UA 1580 arrives on the timetable: more than half a day, so not a connection we count.