The whipping scenes in episode 6 of Outlander were
filmed at Blackness Castle which overlooks the River Forth west of
Filming location was in the courtyard of the castle to the north east of the
centrally placed keep.
The outside of Blackness Castle (with a bit of CGI) appeared in episode 8 of Outlander as Fort William
See Blackness Castle location page for information
on it and the other movies filmed there.