UA 3909 then AC 4530 at San Francisco
Chicago O'Hare → San Francisco → Sacramento
Timetable, San Francisco time
22:20UA 3909 from Chicago O'Hare at the gate
16:10AC 4530 to Sacramento leaves the gate
17 h 50 apart on the timetable, overnight
AC 4530 leaves 17 h 50 after UA 3909 arrives on the timetable: more than half a day, so not a connection we count.